Dexter was asked to mix the punch for his sister’s birthday party. He has to figure out how much water and pure concentrate to add. How many liters of pure concentrate should be added to 10 liters of 20% concentrate to make a 50% concentrate punch?

  6 liters

Step-by-step explanation:

Let x represent the amount of pure concentrate used to make the punch. Then the total amount of concentrate in the punch is ...

 0.20·10 +1.00x = 0.50(10+x)

  x +2 = 0.5x +5 . . . . . eliminate parentheses

  0.5x = 3 . . . . . . . . . . .subtract 2+0.5x

  x = 6 . . . . . . . . . . . . . multiply by 2

6 liters of pure concentrate must be added to make a 50% punch.

answer: 1) twenty-seven times y

              2) twenty-seven multiplied by y