A container holds 32 litres of a solution of acid and water in the ratio 5 : 3. If 12 litres of this solution is taken out and \(7\frac{1}{2}\) litres of water is added, what is the ratio of acid to water in the resulting solution?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 5 : 6
Taking out part of a solution does not change its ratio, so the 20 litres left are still acid and water in the ratio 5 : 3.
Left: \(32-12=20\) litres
Acid \(\displaystyle =20\times\frac{5}{8}=12.5\) litres, water \(\displaystyle =20\times\frac{3}{8}=7.5\) litres
After adding water: water \(=7.5+7.5=15\) litres
Acid : water \(=12.5:15=5:6\)
The new ratio is 5 : 6.