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A tank can be filled by pipe A in 2 hours and pipe B in 6 hours. At 10 A.M. pipe A was opened. At what time will the tank be filled if pipe B is opened at 11 A.M. ?

A. 12.45 A.M.

B. 5 P.M.

C. 11.45 A.M.

D. 12 P.M.

Answer: Option C

Solution(By Examveda Team)

Pipes and Cistern mcq solution image
Pipe A will fill 3 units till 11 A.M. Remaining capacity
= 6 - 3
= 3 units
Now both pipes will fill the tank in
$$\frac{{{\text{Total Capacity}}}}{{{\text{Efficiency }}}} = \frac{3}{{\left( {3 + 1} \right)}} = \frac{3}{4}{\text{ hours}}$$
So, $$\left( {11 + \frac{3}{4}} \right)$$  A.M., tank will be filled = 11.45 A.M.

This Question Belongs to Arithmetic Ability >> Pipes And Cistern

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Comments ( 1 )

  1. Atikur Rahman
    Atikur Rahman :
    4 years ago

    (A+B) can fill in 1 hr= (1/2)+(1/6)=2/3 part
    A can fill in 1 hr=1/2 part of the tank
    So remaining 1/2 part
    2/3 part filled by (A+B) in 1 hr
    So, remaining 1/2 part filled by (A+B)= (3/2)*(1/2)
    =3/4 hr or 45 mins
    So total 1 hr 45 mins.Starting from 10 am the tank will be filled within 11:45 am

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