Two taps P and Q can fill a tank in 12 hours and 18 hours, respectively. Both taps were opened at `7:00` am and after some time, Q was closed. It was found that the tank was full at `3:00` At what time was Q shut ?

Options

A. `10:00` am
B. `12:00` noon
C. `1:00`pm
D. `2:00` pm

Answer

C

Explanation

(i) Tank was filled in 8 hours. P was opened all the time
(ii) Tap P is opened for 8 hours. Let the tap Q be opened for x housr
(iii)`(8)/(12)+(x)/(18)=1`
(iv)