a pharmacist dilutes 18 liters of an 8% solution with a 4.5% solution to make a 6% solution. How many liters of the 4.5% solution are added

Answer 1

8(18) + 4.5X = 6(18+X)

144 + 4.5X = 108 + 6X

1.5X = 144-108 = 136

X = 36/1.5 = 24 liters of 4.5% added to 18 of 8% will give 42 liters of 6% solution

4.5 is within 1.5 of 6

8 is within 2 of 6, so you need more of 4.5 than of 8

2/1.5 = 4/3, so you need 4/3 more of 4.5 solution

4/3(18) = 24 liters of 4.5%