Chlorination is used in industry for the purification of water; 1 gm solution of chlorine will remove half of the...

This topic has expert replies
Moderator
Posts: 2599
Joined: Sun Oct 29, 2017 2:08 pm
Followed by:2 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

GMAT Prep

Chlorination is used in industry for the purification of water; 1 g solution of chlorine will remove half of the germs in 1 liter of water. If the water containing less than 0.09% is considered clean, what is the minimum amount of chlorine required to purify 150 liters of water containing 0.3 liters of harmful substances?

A. 1
B. 2
C. 3
D. 4
E. 5

OA B
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8086
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members
AAPL wrote:
Wed Mar 25, 2020 1:39 am
GMAT Prep

Chlorination is used in industry for the purification of water; 1 g solution of chlorine will remove half of the germs in 1 liter of water. If the water containing less than 0.09% is considered clean, what is the minimum amount of chlorine required to purify 150 liters of water containing 0.3 liters of harmful substances?

A. 1
B. 2
C. 3
D. 4
E. 5

OA B
The water has 0.3 liters of harmful substances and needs to be reduced to less than 0.0009 x 150 = 0.135 liters in order to be considered clean. If we add 1 gram of chlorine to the solution, half of the germs will be removed and we will be left with 0.3 x 1/2 = 0.15 liters of harmful substances. If we add another gram of chlorine, there will be 0.15 x 1/2 = 0.075 liters of harmful substances remaining in the water, which is a low enough figure for the water to be considered clean. Thus, we need 2 grams of chlorine in total.

Answer: B

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage