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27 Dec 2017, 01:10
Kudos
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C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
90% (01:19) correct
10%
(01:21)
wrong
based on 66
sessions
History
Date
Time
Result
Not Attempted Yet
On 3 sales Tom has received commissions of $250, $95, and $175, and has two additional sales pending. If Tom is to receive an average (arithmetic mean) commission of exactly $150 on the 5 sales, then the average (arithmetic mean) of the final two sales must be
A. 60
B. 80
C. 115
D. 230
E. 280
A. 60
B. 80
C. 115
D. 230
E. 280
27 Dec 2017, 01:58
Kudos
Bookmarks
Bunuel
We'll take a shortcut to calculation based on properties of the average.
This is a Logical approach.
Our target is to find two numbers that combine with $250, $95, $175 to give an average of $150.
These three numbers have a difference of 100, -55, 25 from 150 for a combined difference of 100-55+25=70.
So our remaining two numbers need to compensate for this with -70, which is -70/2 = -35 each.
Therefore they must have an average of 150 - 35 = 115.
(C) is our answer.
Note that the calculations here involve much smaller numbers than \(\frac{(150*5 - (250+175+95))}{2}\) which is the straightforward, Precise, approach.
27 Dec 2017, 11:34
Kudos
Bookmarks
Bunuel
\(250 + 95 + 175 + x + y = 150*5\)
Or, \(520 + ( x + y ) = 750\)
Or, ( x + y ) = \(230\)
So, Average from the 2 additional sales must be \(\frac{230}{2} = 115\)
Thus, answer will be (C) 115
