Total fish in a tank











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A tank had 20 clownfish and angelfish. 4 clownfish were sold and some angelfish were added to the tank such that the number of angelfish increased by 50%. After that, there were 18 fish in the tank altogether. How many clownfish were there in the tank at first?



How do I create an algebraic expression for this?










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    A tank had 20 clownfish and angelfish. 4 clownfish were sold and some angelfish were added to the tank such that the number of angelfish increased by 50%. After that, there were 18 fish in the tank altogether. How many clownfish were there in the tank at first?



    How do I create an algebraic expression for this?










    share|cite|improve this question
























      up vote
      -1
      down vote

      favorite









      up vote
      -1
      down vote

      favorite











      A tank had 20 clownfish and angelfish. 4 clownfish were sold and some angelfish were added to the tank such that the number of angelfish increased by 50%. After that, there were 18 fish in the tank altogether. How many clownfish were there in the tank at first?



      How do I create an algebraic expression for this?










      share|cite|improve this question













      A tank had 20 clownfish and angelfish. 4 clownfish were sold and some angelfish were added to the tank such that the number of angelfish increased by 50%. After that, there were 18 fish in the tank altogether. How many clownfish were there in the tank at first?



      How do I create an algebraic expression for this?







      percentages word-problem






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      asked Nov 14 at 6:54









      RukaiPlusPlus

      725




      725






















          2 Answers
          2






          active

          oldest

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          up vote
          1
          down vote













          In the beginning, there are a total of $20$ fish in the tank. Let's mark $C$= number of clownfish in the beginning and $A=$number of angelfish in the beginning. Now we know that
          $$
          C+A = 20
          $$

          Then 4 clownfish were sold, resulting in $C$ getting replaced by $C-4$. Then the number of angelfish is increased by $50~%$, meaning that $A$ is replaced by $frac{3}{2}A$. So at the end we have 18 fish
          $$
          (C-4) + frac{3}{2}A = 18
          $$

          Simplifying the equations, we get the following pair of equations:
          $$
          left{
          begin{array}{cccc}
          C &+ A &=& 20 \
          2C &+ 3A &=& 44
          end{array}
          right.
          $$

          Do you know how to solve this now?






          share|cite|improve this answer





















          • So I'm guessing the reason how you got (3/2)A is because "1" was the total Fish in the beginning, but since it increased by 50%, so you had to add .5 from the "1" to get 1.5.? Hopefully that made sense.
            – RukaiPlusPlus
            Nov 14 at 23:55










          • @RukaiPlusPlus Yes, that is exactly it.
            – Matti P.
            Nov 15 at 8:01


















          up vote
          0
          down vote













          You have $c+a=20$.



          The clownfish were sold, so c becomes $c-4$.



          The angelfish population increases by $50%$, so $a$ become $1.50a$.



          Now, we have $c-4+1.50a=18$.






          share|cite|improve this answer





















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            2 Answers
            2






            active

            oldest

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            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

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            active

            oldest

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            up vote
            1
            down vote













            In the beginning, there are a total of $20$ fish in the tank. Let's mark $C$= number of clownfish in the beginning and $A=$number of angelfish in the beginning. Now we know that
            $$
            C+A = 20
            $$

            Then 4 clownfish were sold, resulting in $C$ getting replaced by $C-4$. Then the number of angelfish is increased by $50~%$, meaning that $A$ is replaced by $frac{3}{2}A$. So at the end we have 18 fish
            $$
            (C-4) + frac{3}{2}A = 18
            $$

            Simplifying the equations, we get the following pair of equations:
            $$
            left{
            begin{array}{cccc}
            C &+ A &=& 20 \
            2C &+ 3A &=& 44
            end{array}
            right.
            $$

            Do you know how to solve this now?






            share|cite|improve this answer





















            • So I'm guessing the reason how you got (3/2)A is because "1" was the total Fish in the beginning, but since it increased by 50%, so you had to add .5 from the "1" to get 1.5.? Hopefully that made sense.
              – RukaiPlusPlus
              Nov 14 at 23:55










            • @RukaiPlusPlus Yes, that is exactly it.
              – Matti P.
              Nov 15 at 8:01















            up vote
            1
            down vote













            In the beginning, there are a total of $20$ fish in the tank. Let's mark $C$= number of clownfish in the beginning and $A=$number of angelfish in the beginning. Now we know that
            $$
            C+A = 20
            $$

            Then 4 clownfish were sold, resulting in $C$ getting replaced by $C-4$. Then the number of angelfish is increased by $50~%$, meaning that $A$ is replaced by $frac{3}{2}A$. So at the end we have 18 fish
            $$
            (C-4) + frac{3}{2}A = 18
            $$

            Simplifying the equations, we get the following pair of equations:
            $$
            left{
            begin{array}{cccc}
            C &+ A &=& 20 \
            2C &+ 3A &=& 44
            end{array}
            right.
            $$

            Do you know how to solve this now?






            share|cite|improve this answer





















            • So I'm guessing the reason how you got (3/2)A is because "1" was the total Fish in the beginning, but since it increased by 50%, so you had to add .5 from the "1" to get 1.5.? Hopefully that made sense.
              – RukaiPlusPlus
              Nov 14 at 23:55










            • @RukaiPlusPlus Yes, that is exactly it.
              – Matti P.
              Nov 15 at 8:01













            up vote
            1
            down vote










            up vote
            1
            down vote









            In the beginning, there are a total of $20$ fish in the tank. Let's mark $C$= number of clownfish in the beginning and $A=$number of angelfish in the beginning. Now we know that
            $$
            C+A = 20
            $$

            Then 4 clownfish were sold, resulting in $C$ getting replaced by $C-4$. Then the number of angelfish is increased by $50~%$, meaning that $A$ is replaced by $frac{3}{2}A$. So at the end we have 18 fish
            $$
            (C-4) + frac{3}{2}A = 18
            $$

            Simplifying the equations, we get the following pair of equations:
            $$
            left{
            begin{array}{cccc}
            C &+ A &=& 20 \
            2C &+ 3A &=& 44
            end{array}
            right.
            $$

            Do you know how to solve this now?






            share|cite|improve this answer












            In the beginning, there are a total of $20$ fish in the tank. Let's mark $C$= number of clownfish in the beginning and $A=$number of angelfish in the beginning. Now we know that
            $$
            C+A = 20
            $$

            Then 4 clownfish were sold, resulting in $C$ getting replaced by $C-4$. Then the number of angelfish is increased by $50~%$, meaning that $A$ is replaced by $frac{3}{2}A$. So at the end we have 18 fish
            $$
            (C-4) + frac{3}{2}A = 18
            $$

            Simplifying the equations, we get the following pair of equations:
            $$
            left{
            begin{array}{cccc}
            C &+ A &=& 20 \
            2C &+ 3A &=& 44
            end{array}
            right.
            $$

            Do you know how to solve this now?







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered Nov 14 at 7:01









            Matti P.

            1,625413




            1,625413












            • So I'm guessing the reason how you got (3/2)A is because "1" was the total Fish in the beginning, but since it increased by 50%, so you had to add .5 from the "1" to get 1.5.? Hopefully that made sense.
              – RukaiPlusPlus
              Nov 14 at 23:55










            • @RukaiPlusPlus Yes, that is exactly it.
              – Matti P.
              Nov 15 at 8:01


















            • So I'm guessing the reason how you got (3/2)A is because "1" was the total Fish in the beginning, but since it increased by 50%, so you had to add .5 from the "1" to get 1.5.? Hopefully that made sense.
              – RukaiPlusPlus
              Nov 14 at 23:55










            • @RukaiPlusPlus Yes, that is exactly it.
              – Matti P.
              Nov 15 at 8:01
















            So I'm guessing the reason how you got (3/2)A is because "1" was the total Fish in the beginning, but since it increased by 50%, so you had to add .5 from the "1" to get 1.5.? Hopefully that made sense.
            – RukaiPlusPlus
            Nov 14 at 23:55




            So I'm guessing the reason how you got (3/2)A is because "1" was the total Fish in the beginning, but since it increased by 50%, so you had to add .5 from the "1" to get 1.5.? Hopefully that made sense.
            – RukaiPlusPlus
            Nov 14 at 23:55












            @RukaiPlusPlus Yes, that is exactly it.
            – Matti P.
            Nov 15 at 8:01




            @RukaiPlusPlus Yes, that is exactly it.
            – Matti P.
            Nov 15 at 8:01










            up vote
            0
            down vote













            You have $c+a=20$.



            The clownfish were sold, so c becomes $c-4$.



            The angelfish population increases by $50%$, so $a$ become $1.50a$.



            Now, we have $c-4+1.50a=18$.






            share|cite|improve this answer

























              up vote
              0
              down vote













              You have $c+a=20$.



              The clownfish were sold, so c becomes $c-4$.



              The angelfish population increases by $50%$, so $a$ become $1.50a$.



              Now, we have $c-4+1.50a=18$.






              share|cite|improve this answer























                up vote
                0
                down vote










                up vote
                0
                down vote









                You have $c+a=20$.



                The clownfish were sold, so c becomes $c-4$.



                The angelfish population increases by $50%$, so $a$ become $1.50a$.



                Now, we have $c-4+1.50a=18$.






                share|cite|improve this answer












                You have $c+a=20$.



                The clownfish were sold, so c becomes $c-4$.



                The angelfish population increases by $50%$, so $a$ become $1.50a$.



                Now, we have $c-4+1.50a=18$.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Nov 14 at 7:00









                Saketh Malyala

                7,3011534




                7,3011534






























                     

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