Two friends are making lemonade to sell at their lemonade stand. First, they make 14 litres of lemonade containing 21% lemon juice, but that doesn't taste quite right to them. They decide to add some store-bought lemonade that is 31% lemon juice until they have a mixture that is 25% lemon juice. How much of the store-bought lemonade should they add?  Choose the correct choice
A) 6.6 litres B) 12 litres C) 9 litres D) 2.6 litres E) 9.3 litres
0.21(14)+0.31x = 0.25(14 + x)   Solve the equation.   0.21(14) + 0.31x = 0.25(14 + x)   2.94 + 0.31x = 3.5 + 0.25x   2.94 + 0.06x = 3.5   0.06x = 0.56   x ≈ 9.3   Answer is 9.3 litres.
<result>E</result>
Two friends are making lemonade to sell at their lemonade stand. First, they make 14 litres of lemonade containing 21% lemon juice, but that doesn't taste quite right to them. They decide to add some store-bought lemonade that is 31% lemon juice until they have a mixture that is 25% lemon juice. How much of the store-bought lemonade should they add?