Three taps P Q and R can fill a tank in 10 20 and 30 hours respectively If A is open all the ti...........

Quantitative Aptitude ( CCS) Pipes&cistern

Three taps P,Q and R can fill a tank in 10,20 and 30 hours respectively. If A is open all the time and Q and R are open for one hour each alternatively ,the tank will be fill in ?

7 hours

7 hours 30min

7hours 45min

7hours 20 min

छोटे Courses बड़े Results

Master Pipes&cistern

Prepare through Micro-courses

Try Now

Explanation:

Answer – 7 hours
Explanation :
A+B in 1 hr =(1/10)+(1/20) = (2+1)/20 = 3/20
A+C in 1 hr =(1/10)+(1/30) = (3+1)/20 = 4/30
In 2 hr => (3/20)+(4/30) = (9+8)/60 = 17/60
Part filled in 6 hours =3×(17/60) = 17/20
Remaining part = 1-(17/20) =(20 – 17)/20= 3/20(filled by A and B)……1hour
Total time taken to fill the tank = 6+1 = 7 hour