how much water must be added to 60kgs of an 80% acid solution to produce a 50% solution

Question

i need help with my ans please

Answer 1

W=weight of water, S=weight of 50% solution. Amount of water in 80% acid solution is 20% (1/5).

Equating weights: W+60=S; equating amount of water: W+60/5=S/2; 2W+24=S=W+60; W=60-24=36kg, S=W+60=96kg. Therefore, the amount of water is 36kg.

CHECK: Weight of water in 50% solution is 96/2=48kg. Weight of water in 80% solution is 20% of 60kg=12kg. 36+12=48 kg of water, so amounts of water add up correctly.