GMAT PREP I #8

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 266
Joined: Mon Oct 19, 2009 9:46 pm
Thanked: 8 times
GMAT Score:690

GMAT PREP I #8

by pkw209 » Thu Dec 10, 2009 5:52 pm
Hi all,

Couldn't figure this one out. Would appreciate a brief explanation. thanks!

Q) In a certain year, the difference between M and J's annual salaries was twice the difference between M and K's annual salaries. If M's annual salary was the highest of the 3 people, what was the average annual salary of the 3 people that year?

1) J's annual salary was 30K that year

2) K's annual salary was 40K that year
Source: — Data Sufficiency |

User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pm
Thanked: 653 times
Followed by:252 members

by papgust » Thu Dec 10, 2009 8:28 pm
I guess it should be C

M-J = 2(M-K)
M-J = 2M-2K
2K-J = M ....... (1)

1. J=30,000

We don't know about K's/M's salary to find the average. Insufficient.

2. K=40,000

Again, we don't know about J's/M's salary to find the average. Insufficient.

Combined, we know J's and K's salary. Using that we can find M's salary. We can find the average then. Sufficient.

Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Fri Dec 04, 2009 8:56 am
Thanked: 1 times

by SonalGhai » Thu Dec 10, 2009 10:27 pm
pkw209 wrote:Hi all,

Couldn't figure this one out. Would appreciate a brief explanation. thanks!

Q) In a certain year, the difference between M and J's annual salaries was twice the difference between M and K's annual salaries. If M's annual salary was the highest of the 3 people, what was the average annual salary of the 3 people that year?

1) J's annual salary was 30K that year

2) K's annual salary was 40K that year

The answer to this question would be 'B'.

If we convert the question given here in mathematical term:
M-J=2(M-K)
M-J=2M-2k
K=(M+J)/2

So, If we know only K that would suffice in finding the average salary.

As Avg. would be (M+J+K)/3 .Substitute for M+J=2k .So we get the avg. as K salary and thats provided in B.

User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pm
Thanked: 653 times
Followed by:252 members

by papgust » Fri Dec 11, 2009 12:38 am
Nicely done! Thanks for pointing it out!