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What is the average (arithmetic mean) of all the multiples
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31 Jan 2018, 05:44
31 Jan 2018, 05:44
1
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Question Stats:
78% (00:35) correct
21% (00:33) wrong based on 28 sessions
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What is the average (arithmetic mean) of all the multiples of ten from 10 to 190 inclusive?
A) 90
B) 95
C) 100
D) 105
E) 110
A) 90
B) 95
C) 100
D) 105
E) 110
Show: ::
C
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: What is the average (arithmetic mean) of all the multiples
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31 Jan 2018, 11:15
31 Jan 2018, 11:15
2
amorphous wrote:
What is the average (arithmetic mean) of all the multiples of ten from 10 to 190 inclusive?
A) 90
B) 95
C) 100
D) 105
E) 110
A) 90
B) 95
C) 100
D) 105
E) 110
Show: ::
C
There's a nice rule that says, "In a set where the numbers are equally spaced, the mean will equal the median."
For example, in each of the following sets, the mean and median are equal:
{7, 9, 11, 13, 15}
{-1, 4, 9, 14}
{3, 4, 5, 6}
There's another nice rule that says, In a set where the numbers are equally spaced, the mean = (largest value + smallest value)/2
The multiples of ten from 10 to 190 inclusive are equally spaced, so the median = the mean
So, the mean = median = (10 + 190)/2 = 100
Answer: C
Cheers,
Brent
Re: What is the average (arithmetic mean) of all the multiples
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27 Mar 2018, 10:27
27 Mar 2018, 10:27
1
10 * (1+2+3+...19). Then 19+1 (9.5) = 190. So, (10 (190)) / 19 ( the number of values) = 100
