gmat paper test 25

[payam]

removed by moderator JNelson

[GMAT 2007]

The question is incomplete. Please repost.

[payam]

removed by moderator JNelson

[givemeanid]

Number who exceed speed limit = E
Total motorists = M

20% of who exceed do not get tickets.
So, 80% of who exceed get tickets = 10% of total

80% of E = 10% of M
0.8E = 0.1M
E/M = 0.1/0.8 = 1/8 = 12.5%

[ved_vishwa]

On a certain road 10 percent of the motorists exceed
the posted speed limit and receive speeding tickets,
but 20 percent of the motorists who exceed the posted
speed limit do not receive speeding tickets. What
percent of the motorists on the road exceed the posted
speed limit?
(A) 2
10 1 %
(B) 2
12 1 %
(C) 15%
(D) 22%
(E) 30%

Let there be a total of T number of motorists on the road.
Assume there are X number of motorists who have exceeded the speed limit.
Now, 1st part of the question tells us that the number of motorists who exceed speed limit and are fined = 0.10T---(1)
And, later part of the question tells us that the number of motorists who exceed speed limit and are 'not' fined = 0.20X---(2)
From (1) and (2), it follows that:
0.20X + 0.10T = X
Upon solving, you will get (X/T)*100 = (1/8)*100 = 12.5%.

[jnelson0612]

Sorry all, but the GMAT official questions are banned sources here by request of the GMAC. Unfortunately I've had to remove all the posts about this question. Please read the forum guidelines: read-before-you-post-general-math-folder-guidelines-t2717.html