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singhmaharaj: Senior | Next Rank: 100 Posts; Posts: 38; Joined: Tue Feb 10, 2009 6:24 amFollowed by: 2 members; Location: Hong Kong

by singhmaharaj » Tue May 06, 2014 5:13 am

A certain meter records voltage between 0 volts and 10 volts, inclusive. If the average (arithmetic mean) value of 3 recordings on the meter was 8 volts, what was the smallest possible recording, in volts?

A) 2

B) 3

C) 4

D) 5

E) 6

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Source: Beat The GMAT — Problem Solving | Tue May 06, 2014 5:13 am

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Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members; Location: Vancouver, BC; Thanked: 5254 times; GMAT Score:770

by Brent@GMATPrepNow » Tue May 06, 2014 5:23 am

singhmaharaj wrote:A certain meter records voltage between 0 volts and 10 volts, inclusive. If the average (arithmetic mean) value of 3 recordings on the meter was 8 volts, what was the smallest possible recording, in volts?

A) 2
B) 3
C) 4
D) 5
E) 6

Sum of values = (# of values)(mean)
So, sum of the 3 readings = (3)(8) = 24

To MINIMIZE one of the readings, we must MAXIMIZE the other two readings.
The maximum reading is 10, so let two of the readings equal 10.

Since the sum of all 3 readings must be 24, the last remaining reading must equal 4

Answer: C

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

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Brent@GMATPrepNow: GMAT Instructor; Posts: 16207; Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members; Location: Vancouver, BC; Thanked: 5254 times; GMAT Score:770

by Brent@GMATPrepNow » Tue May 06, 2014 5:24 am

For some reason, my response got posted twice. I erased the 2nd one.

Cheers,
Brent

Brent Hanneson - Creator of GMATPrepNow.com

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Scott@TargetTestPrep: GMAT Instructor; Posts: 8136; Joined: Sat Apr 25, 2015 10:56 amFollowed by: 29 members; Location: Los Angeles, CA; Thanked: 43 times

by Scott@TargetTestPrep » Thu Oct 18, 2018 5:22 pm

singhmaharaj wrote:A certain meter records voltage between 0 volts and 10 volts, inclusive. If the average (arithmetic mean) value of 3 recordings on the meter was 8 volts, what was the smallest possible recording, in volts?

A) 2

B) 3

C) 4

D) 5

E) 6

To make one number as small as possible, the other two numbers must be as large as possible. Thus, we will let the two greatest voltage readings be 10, and he lowest reading be n and create the equation for the average of the 3 readings:

(n + 10 + 10)/3 = 8

n + 20 = 24

n = 4

Answer: C

Scott Woodbury-Stewart
Founder and CEO
[email protected]

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