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## What is the average (arithmetic mean) of w, x, y, z, and 10?

tagged by: M7MBA

This topic has 2 expert replies and 0 member replies

### Top Member

M7MBA Moderator
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#### What is the average (arithmetic mean) of w, x, y, z, and 10?

Thu Mar 01, 2018 6:43 am
What is the average (arithmetic mean) of w, x, y, z, and 10?

(1) The average (arithmetic mean) of w and y is 7.5; the average (arithmetic mean) of x and z is 2.5
(2) -(-z - y -x - w) = 20

The OA is the option D.

How can I use statement (1) to get an answer here? Experts, may you help me? I'd be thankful.

### GMAT/MBA Expert

Jay@ManhattanReview GMAT Instructor
Joined
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Wed Mar 07, 2018 3:01 am
M7MBA wrote:
What is the average (arithmetic mean) of w, x, y, z, and 10?

(1) The average (arithmetic mean) of w and y is 7.5; the average (arithmetic mean) of x and z is 2.5
(2) -(-z - y -x - w) = 20

The OA is the option D.

How can I use statement (1) to get an answer here? Experts, may you help me? I'd be thankful.
We have to get the average (arithmetic mean) of w, x, y, z, and 10.

The average (arithmetic mean) of w, x, y, z, and 10 = (w + x + y + x + 10)/5.

If we get the value of (w + x + y + x), we get the answer.

Let's take each statement one by one.

(1) The average (arithmetic mean) of w and y is 7.5; the average (arithmetic mean) of x and z is 2.5.

=> (w + y)/2 = 7.5 => w + y = 15
=> (x + z)/2 = 2.5 => x + z = 5

=> w + x + y + x = 15 + 5 = 20. Unique answer. Sufficient.

(2) -(-z - y -x - w) = 20

=> z + y +x + w = 20. Unique answer. Sufficient.

Hope this helps!
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### GMAT/MBA Expert

mbawisdom Senior | Next Rank: 100 Posts
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GMAT Score:
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Tue Mar 06, 2018 6:07 am
M7MBA wrote:
What is the average (arithmetic mean) of w, x, y, z, and 10?

(1) The average (arithmetic mean) of w and y is 7.5; the average (arithmetic mean) of x and z is 2.5
(2) -(-z - y -x - w) = 20

The OA is the option D.

How can I use statement (1) to get an answer here? Experts, may you help me? I'd be thankful.
We want to find out what (w + x + y + z + 10)/5 equals.

(1) tells us that (w + y)/2 = 7.5 or that w + y = 15, it also tells us that (x + z)/2 = 2.5 or that x + z = 5
Thus, we can use this to put into equation
(w + x + y + z + 10)/5
((x + z) + (w + y) + 10)/5
(5 + 15 + 10)/5
30/5
6

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