Question

A Chemist has 100g of 25% acid solution. How much of these solution he needs to drain and replace with 70% acid solution to obtain 100g of 60% acid solution?

Answer 1

let us assume x=amt of 25% solution to drain and replace with 70% solution 25%

25%(100-x)+70%x=60%100

25-.25x+.70x=60

.50x=35

x=70

so he needs to drain and replace 70 mg of these solution to obtain 100g of 60% acid solution.