Question

Pipe A can fill a tank in $10h$ and pipe $B$ can fill the same tank in $12h$. Both the pipes are opened to fill the tank and after $3h$ pipe $A$ is closed. Pipe $B$ will fill the remaining part of the tank in

• A. $5h$
• B. $4h$
• C. $5h$ $24min$
• D. $3h$

Answer 1

The correct option is C $5h$ $24min$

Let capacity of tank = V liters

Speed of A = V/10 lit/hour

B = V/12 lit/hour

In 3hrs both fill $=3\left(\frac{V}{10}\right)+3\left(\frac{V}{12}\right)=3V\left(\frac{11}{60}\right)$

$=33V/60$ Remaining $27V/60$

B fills remaining $=\frac{\frac{27V}{60}}{\frac{V}{12}}=\frac{27}{5}=5hr.24min$

$\Rightarrow \left(c\right)$