Question

Three pipes A, B and C can fill a tank in 20 min, 10 min and 30 min respectively. When the tank is empty, all the three pipes are opened. A, B, C discharge chemical solutions 'x', 'y', 'z' respectively. The proportion of solution 'y' in the liquid in the tank after 3 min is

• A. $\frac{6}{11}$
• B. $\frac{8}{11}$
• C. $\frac{7}{11}$
• D. $\frac{5}{11}$

Answer 1

Answer: (A)

$\frac{6}{11}$

Answer 2

Filling done by all 3 pipes in 3 minutes $=\frac{3}{20}+\frac{3}{10}+\frac{3}{30}=\frac{11}{20}$
Filling done by 2nd pipe in 3 minutes $=\frac{3}{10}$
So, required ratio $=\frac{\frac{3}{10}}{\frac{11}{20}}=\frac{6}{11}$
The correct option is (A)