Question

A tank is filled in 4 hours by three pipes A, B and C. Pipe C is twice as fast as pipe B and pipe B is twice as fast as pipe A. How much time will pipe A take to fill the tank?

• A. 25 hours
• B. 28 hours
• C. 20 hours
• D. 26 hours

Answer 1

Answer:

B. 28 hours

time taken for fill a tank with pipes $A,B,C=4hrs$

efficiency of $A=x$

efficiency of $B=2x$

efficiency of $c=4x$

the ratio of efficiency$=1:2:4$

so the total efficiency $=7$

the total volume of tank $=7\times4=28$

Pipe A will take $=28/1=28hrs$ to fill the tank