Question

Two mixtures a and b contain milk and water in the ratios 2:5 and 5:4 respectively. How many gallons of a must be mixed with 90 gallons of b so that the resultant mixture contains 40% milk?

Answer 1

Answer:

Mixture A: 2:5 ratio of Milk:Water

Mixture B: 5:4 ratio of Milk:water

90 gallons mixture B with a ratio of 5:4 = 50 gallons of milk and 40 gallons of water 90/(5+4) = 10. 10*5 = 50 and 10*4 = 40.

(50+(2/7x))/(90+x) = .40

50+(2/7x)=.4(90+x)

50+(2/7x)=(2/5x)+36

50+(10/35x)=(14/35x) +36

4/35x=14

4x=14*35

4x=490

x=122.5 gallons

that's how you would solve it out step-by-step mathematically. Hope that helps, let me know if you have any questions 8-)