A solution of 120 liters contains 40% acid. How much pure acid (in liters) must be added to make the solution 60% acid?
Show answer & explanation
Correct answer: A
Explanation
40% of 120 liters = 48 liters
Quantity of added acid = x liters
New quantity of acid = 48 + x
New total quantity = 120 + x
48 + x = 60% of (120 + x)
48 + x = 60/100 × (120 + x)
48 + x = 72 + 0.6x
x - 0.6x = 72 - 48
0.4x = 24
x = 60