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The average (arithmetic mean) of five numbers is 88. Four of the numb
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25 May 2021, 19:58
25 May 2021, 19:58
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Question Stats:
87% (00:42) correct
12% (01:32) wrong based on 24 sessions
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The average (arithmetic mean) of five numbers is 88. Four of the numbers are 92, 89, 91.....84. What is the fifth number?
(A) 82
(B) 84
(C) 86
(D) 89
(E) 92
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
(A) 82
(B) 84
(C) 86
(D) 89
(E) 92
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
The average (arithmetic mean) of five numbers is 88. Four of the numb
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26 May 2021, 07:46
26 May 2021, 07:46
1
This is a typical GRE question which tests averages.
Solution:
Avg=\(\frac{Sum of all numbers}{Total number of numbers}\)
88=\(\frac{Sum of all numbers}{5}\)
Sum of all numbers= 440
440-92-89-91-84=84
Thus the fifth term is 84
Hope this helps!
Solution:
Avg=\(\frac{Sum of all numbers}{Total number of numbers}\)
88=\(\frac{Sum of all numbers}{5}\)
Sum of all numbers= 440
440-92-89-91-84=84
Thus the fifth term is 84
Hope this helps!
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The average (arithmetic mean) of five numbers is 88. Four of the numb
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30 Jun 2022, 09:14
30 Jun 2022, 09:14
Theory: Average = \(\frac{Sum Of All The Values}{Total Number Of Values}\)
Let's solve the problem using two methods
Method 1: Algebra
If the average (arithmetic mean) of 5 numbers is 88 and four of the numbers are 92, 89, 91 and 84
Let the fifth number be x
=> Sum of all the values = 92 + 89 + 91 + 84 + x = 356 + x
Using, Average = \(\frac{Sum Of All The Values}{Total Number Of Values}\), We get
88 = \(\frac{356 + x }{ 5}\) (dividing by 5 as there are 5 numbers)
=> 356 + x = 88*5 = 440
=> x = 440 - 356 = 84
So, Answer will be B
Method 2: Logic (Net Deviation from Mean =0)
Sum of net deviation of all the values from the mean should be equal to zero
92 - 88 (Mean) = 4
89 - 88 (Mean) = 1
91 - 88 (Mean) = 3
84 - 88 (Mean) = -4
=> Sum of Net deviation = 4 + 1 + 3 + (-4) = 4
=> To make sum of net deviation to be zero fifth value should have a deviation of 0-4 = -4
=> Fifth value should be -4 from 88 => 88-4 = 84
So, Answer will be B
Hope it helps!
To learn more about Statistics watch the following video
Let's solve the problem using two methods
Method 1: Algebra
If the average (arithmetic mean) of 5 numbers is 88 and four of the numbers are 92, 89, 91 and 84
Let the fifth number be x
=> Sum of all the values = 92 + 89 + 91 + 84 + x = 356 + x
Using, Average = \(\frac{Sum Of All The Values}{Total Number Of Values}\), We get
88 = \(\frac{356 + x }{ 5}\) (dividing by 5 as there are 5 numbers)
=> 356 + x = 88*5 = 440
=> x = 440 - 356 = 84
So, Answer will be B
Method 2: Logic (Net Deviation from Mean =0)
Sum of net deviation of all the values from the mean should be equal to zero
92 - 88 (Mean) = 4
89 - 88 (Mean) = 1
91 - 88 (Mean) = 3
84 - 88 (Mean) = -4
=> Sum of Net deviation = 4 + 1 + 3 + (-4) = 4
=> To make sum of net deviation to be zero fifth value should have a deviation of 0-4 = -4
=> Fifth value should be -4 from 88 => 88-4 = 84
So, Answer will be B
Hope it helps!
To learn more about Statistics watch the following video
