75.4k views
2 votes
Two taps A and B can fill a tank in 10 minutes and 15 minutes respectively. In what time will the tank be full if tap B was opened 3 minutes after tap A was opened ?

A. 6 min 12 s
B. 7 min 12 s
C. 8 min 12 s
D. 9 min 12 s

User Rebecca
by
8.9k points

1 Answer

5 votes

The time that the tank will be full if tap B was opened 3 minutes after tap A was opened is D. 9 min 12 s

How to find the time ?

Tap A can fill the tank in 10 minutes, so R_A = 1/10 tank per minute.

Tap B can fill the tank in 15 minutes, so R_B = 1/15 tank per minute.

For the first 3 minutes, only tap A is open, so it fills:

3 minutes x R_A = 3 x (1/10)

= 3/10 of the tank

To find the remaining time to fill the tank, we can use the formula:

Time = Amount to be filled / Rate

Time = 1 / (1/6) = 6 minutes 12 seconds

Now, add the 3 minutes it took tap A to fill the initial portion:

Total time = 6 minutes + 3 minutes

= 9 minutes 12 seconds

User Andrei Sosnin
by
7.6k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories