Question

Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?

• A. 5/11
• B. 6/11
• C. 7/11
• D. 8/11
• E. 9/11

Answer 1

The correct option is B

6/11

Part filled by (A + B + C) in 3 minutes = $3(\frac{1}{30}+\frac{1}{20}+\frac{1}{10})$ = $(3\times \frac{11}{60})$ = $\frac{11}{20}$

Part filled by C in 3 minutes = $\frac{3}{10}$

$\therefore$ Required ratio $=(\frac{3}{10}\times \frac{20}{11})=\frac{6}{11}$