GMAT prep % DS

[Guest]

Jasons salary and Karens salary were each p percent greater in 1998 than in 1995 .What is the value of p ?

1) In 1995 Karens Salary was 2000 greater than Jasons
2) In 1998 Karens salary was 2440 greater than Jasons

Please explain ?

[dingo001]

Here is why

AD is out because 1 is insuf, similarly B is out, 2 is insuf

Now combining 1 and 2 u get
K=J+2000 in 95
K=J+2440 in 98

Pick a num for J, but u dont know what J was in 95 or in 98. So E is answer.

OA?

[Guest]

Unfortunately i dont hv the OA ...cud someone please confirm if it is E ..thnks in advance

[StaceyKoprince]

If you do not know the official answer, where did you get this problem? It should only be posted in this thread if you know that it came from GMATPrep - and if you saw it in GMATPrep, you should also have the answer... please verify the source for this problem.

[Guest]

I got it from beattgegmat and it is a GMAT prep question :) ..i posted it here because the discussion was inconclusive and still is at that stage :D


Now that authenticity has been validated could someone please confirm :)

[Guest]

http://www.beatthegmat.com/gmat-prep-pr ... t6931.html
The OA seems to be C ..i dont understand how ?? ..

[RonPurewal]

You could translate this problem into the following terms:
k = Karen's 1995 salary
j = Jason's 1995 salary
p = already defined in the problem

Then we'd have

(1) k = j + 2000
(2) k(1 + p/100) = j(1 + p/100) + 2440

together: substitute j + 2000 for the first 'k'
(j + 2000)(1 + p/100) = j(1 + p/100) + 2440
2000(1 + p/100) = 2440
...so you can calculate p.

--

Alternatively, just look at it this way: If you increase a bunch of quantities all by the same percentage, then ALL the differences between those quantities increase by the same percentage. (If my brother weighs 10 pounds more than I do, and both of us gain 10% more weight, then he'll now weigh 10% more than 10 = 11 pounds more than I will.)

So whatever is the % increase from 2000 to 2440, must also be the percent increase in the salaries as well (and hence = p). And this is exactly what the reduced equation above, 2000(1 + p/100) = 2440, says: it says that 2000, increased by p%, yields 2440.

[RonPurewal]

Oh yeah, I forgot to say, that makes the answer C.