Question

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

• A. 5 hours
• B. 4 hours
• C. 5 hours 24 min
• D. 3 hours

Answer 1

Answer: (C)

5 hours 24 min

Pipe A can Fill in = 10 hours
Pipe B can Fill in=12 hours
According to the question,
$\Rightarrow \frac{3}{10}+\frac{x+3}{12}=1$
$\Rightarrow \frac{x+3}{12}=\frac{7}{10}$
$\frac{x+3}{6}=\frac{7}{5}$
$\Rightarrow 5x+15=42$
$5x=27$
$x=\frac{27}{5}or5hr\frac{2}{5}\times 60=5hr24min$