Question

A tap can fill half of a cistern in 30minutes.How long will it take to fill 3/4th of the cistern
Il be grateful if you can help me..My brain is not really working these days,I need to submit this assignment by tomorrow so please help

Answer 1

Answer:

12. A tap can fill a tank in 4 hours. After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the tank completely?

A. 1 hr 30 min B. 2 hr 30 min

C. 2 hr D. 3 hr

Answer: Option B

Explanation:

Solution 1

A tap can fill a tank in 4 hours.

Therefore the tap can fill half the tank in 2 hours.

Remaining part

=

1

2

After half the tank is filled, three more similar taps are opened.

Hence, total number of taps becomes 4.

Part filled by one tap in

1

hour

=

1

4

Part filled by four taps in 1 hour

=

4

×

1

4

=

1

i.e.,

4

taps can fill remaining half in

30

minutes.

Total time taken

=

2

hour +

30

minute =

2

hour

30

minutes