A scientist has two solutions

Question

A scientist has two solutions, which she has labeled Solution A and Solution B. Each contains salt. She knows that Solution A is 55%

 salt and Solution B is 80%

salt. She wants to obtain 90

 ounces of a mixture that is 70%

 salt. How many ounces of each solution should she use? 

Answer 1

Answer is 36 oz for A and 54 oz for B

Answer 2

Typical mixture problem. Focus on the ozs of salt in each solution and the target mixture.

A = oz of sol'n A

B = oz of sol'n B Target solution 90 oz @ 70% salt.

B = 90 - A

The amount of salt in the solutions: 0.55A + 0.8(90- A) = 0.70(90)

0.55A + 72 - 0.8A = 63

-0.25A = -9 so A = 36 oz @ 55%; B = 54 oz @ 80%

Check: A 0.55(36) = 19.8 oz salt; B 0.8(54) = 43.2 oz salt. Total 63 oz salt in 90 oz of sol'n = 70% salt soln.