Pipe A can fill an empty tank in 6 hours and pipe B in 8 hours. If both the pipes are opened and after 2 hours pipe A is closed, how much time B will take to fill the remaining tank?
Pipe A can fill an empty tank in 6 hours and pipe B in 8 hours. If both the pipes are opened and after 2 hours pipe A is closed, how much time B will take to fill the remaining tank?
[A]$latex 2\tfrac{1}{3}\ hours&s=1$
[B]$latex 3\tfrac{1}{3}\ hours&s=1$
[C]$latex 2\tfrac{2}{5}\ hours&s=1$
[D]$latex 7\tfrac{1}{2}\ hours&s=1$
$latex 3\tfrac{1}{3}\ hours&s=1$
Part of the tank filled by pipe A and B in 2 hours
$latex = 2\left ( \frac{1}{6}+\frac{1}{8} \right )&s=1$
$latex = 2\left ( \frac{4+3}{24} \right ) = \frac{7}{12}&s=1$
Remaining part $latex = 1-\frac{7}{12} = \frac{5}{12}&s=1$
This part is filled by pipe B.
∴ Required Time $latex = \frac{5}{12}\times 8 = \frac{10}{3} = 3\frac{1}{3}\ hours&s=1$
Hence option [B] is correct answer.