There are two water tanks A and B. Tank A originally contain

This topic has expert replies
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 am
Location: Las Vegas, USA
Thanked: 19 times
Followed by:37 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

[GMAT math practice question]

There are two water tanks A and B. Tank A originally contains 100 liters of water and Tank B originally contains 20 liters of water. 5 liters of water is poured out of tank A every minute and, at the same time, 3 liters of water is poured into tank B every minute. How long will it take for the tanks to contain the same volume of water?

A. 10 min
B. 12 min
C. 15 min
D. 20 min
E. 22 min
Source: — Problem Solving |

Legendary Member
Posts: 2499
Joined: Sun Oct 29, 2017 2:04 pm
Followed by:6 members

by swerve » Thu Aug 08, 2019 11:40 am
For Tank \(A\), we have
100 \(l\) - 5 \(l/min\)

For Tank \(B\), we have
20 \(l\) + 3\(l/min\)

Therefore,
\(100-(5/t) = 20+(3/t)\quad\Rightarrow\quad t = 10\, min\)

User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 am
Location: Las Vegas, USA
Thanked: 19 times
Followed by:37 members

by Max@Math Revolution » Sun Aug 11, 2019 11:49 pm
=>

The amount of water in the tank A after m minutes is 100 - 5m and the amount of water in the tank B after m minutes is 20 + 3m.
Equating these volumes yields 100 - 5m = 20 + 3m, or 8m = 80.
Thus, m = 10.

Therefore, A is the answer.
Answer: A