If the average (arithmetic mean) of the four numbers 3, 15, 32, and (N

Question

If the average (arithmetic mean) of the four numbers 3, 15, 32, and (N + 1) is 18, then N =

(A) 19
(B) 20
(C) 21
(D) 22
(E) 29

Kudos for a correct  solution .

avigutman · Accepted Answer

Video solution from Quant Reasoning: Subscribe for more: https://www.youtube.com/QuantReasoning? ... irmation=1 https://www.youtube.com/watch?v=URB7KIEHcMU

Skywalker18 · Answer

3+15+32+N+1= 18 x 4 = 72
=>N +51 = 72
=>N=21
Answer C

BrentGMATPrepNow · Answer

The average (arithmetic mean) of the four numbers 3, 15, 32, and (N + 1) is 18  
So, (sum of all 4 numbers)/4 = 18
Multiply both sides by 4 to get: sum of all 4 numbers = 72
This means that 3 + 15 + 32 + (N+1) = 72
Simplify: N + 51 = 72
Solve to get: N = 21

Answer: C

paidlukkha · Answer

(3+15+32+N+1)/4=18
51+N=18*4
N=72-51
N=21

Is this approach correct?

Abhishek009 · Answer

Total of 4 numbers is 14*8 = 72

Total of 3 numbers is 50 (3+15+32)

So, N+1 = 22

Or N = 21

Divyadisha · Answer

3+15+32+N+1/4= 18

N= 18*4 - 51= 21

stonecold · Answer

Here is my solution to this one-->

Suing the concept of mean =>

Mean =\frac{Sum}{#}

\frac{51+n}{4}=18 
Hene n=72-51 = 21
Hence C

Abhishek009 · Answer

3 + 15 + 32 + ( N + 1 ) = 72

Or, N + 51 = 72

So, N = 21
  
Hence, answer will be (C) 21

anum23 · Answer

To answer this, we need to find the sum of the 4 numbers which equals 51+N

we know that average x no. of numbers = sum hence 18 * 4= 51+ N, solving which gives us N=21

ScottTargetTestPrep · Answer

(3 + 15 + 32 + (N + 1))/4 = 18

51 + N = 72

N = 21

Answer: C

energetics · Answer

A different way for practice, consider how far each number is from the average of 18:

-15 + -3 + 14 + (n+1) = 18
-4 + (n+1) = 18
n - 3 = 18
n = 21

Kinshook · Answer

If the average (arithmetic mean) of the four numbers 3, 15, 32, and (N + 1) is 18, then N =

3 + 15 + 32 + (N+1) = 18*4
51 + N = 72
N = 72 -51 = 21

IMO C

Abhishek009 · Answer

3 + 15 + 32 + (N + 1) = 72

Or,  51 + N = 72

Or,  N = 21  , Answer must be (C)

BijayKru · Answer

3, 15,32 , N+1 /4 = 18

So 50+N+1 = 18*4=>72

So N= 72-50-1= 21

GMATinsight · Answer

Answer: Option C

Video solution by  GMATinsight

https://www.youtube.com/watch?v=QlydUH9YoeE

MathRevolution · Answer

Let all numbers are 18 so that average is 18.

3 : 3 - 18 (-15 less)
15 : 15 - 18 (-3 less)
32 : 32 - 18 (14 more)

Therefore, we have -15 - 3 + 14 = -4

We are 4 short and therefore N + 1 should be 4 more than 18 which is 22.

=> N + 1 = 22 and therefore N = 21.

Answer C

vgbarros · Answer

Hey! Another way of solving this question: our list is  , the average of the two terms   +1 is 18 (3+32+1 /2 =18). So, 15+N should be 36 (because 15+N /2 must also be 18), then N=21.

bumpbot · Answer

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If the average (arithmetic mean) of the four numbers 3, 15, 32, and (N

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