The average of 12 numbers is 16. When one number is discarded and 15 is added,

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AAPL: Moderator; Posts: 2599; Joined: Sun Oct 29, 2017 2:08 pm; Followed by:2 members

The average of 12 numbers is 16. When one number is discarded and 15 is added,

by AAPL » Fri Oct 02, 2020 5:53 am

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The average of 12 numbers 16. When one number is discarded and 15 is added, the average becomes 17. What is the number that is discarded?

A. 3
B. 5
C. 6
D. 10
E. 12

OA A

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Source: Beat The GMAT — Problem Solving | Fri Oct 02, 2020 5:53 am

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Scott@TargetTestPrep: GMAT Instructor; Posts: 8086; Joined: Sat Apr 25, 2015 10:56 am; Location: Los Angeles, CA; Thanked: 43 times; Followed by:29 members

Re: The average of 12 numbers is 16. When one number is discarded and 15 is added,

by Scott@TargetTestPrep » Mon Oct 05, 2020 6:52 am

AAPL wrote: ↑
Fri Oct 02, 2020 5:53 am
GMAT Paper Tests

The average of 12 numbers 16. When one number is discarded and 15 is added, the average becomes 17. What is the number that is discarded?

A. 3
B. 5
C. 6
D. 10
E. 12

OA A

Solution:

Since the average of 12 numbers is 16, the sum of those numbers is 12 x 16 = 192.

We can let x = the discarded number and we can create the following equation:

(192 - x + 15)/12 = 17

207 - x = 204

x = 3

Answer: A

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