Highway Tix-from Powerprep

[drhomler]

On a certain highway 10% of the motorists exceed the posted speed limit and receive tix. But 20% of the motorists who exceed the posted speed limit do not receive tix. What percent of the motorists on that road exceed the posted speed limit.

A)10.5%
B)12.5%
C)15%
D)22%
E)30%

[jayhawk2001]

Let M be total num of motorists and E be the portion of Motorists that
exceed the speed limit.

20% of E don't get tix, so 80% of E get tix.

We know 10% M exceed and get tix.

So, 80%E = 10%M

%E/M = 10/80*100 = 12.5%

[drhomler]

Spot on Jay a always. This one tripped me up with the wording but I did get it right on the test. Man some of the word problems give me such trouble because I cant understand what they are saying. Its that "who" in the second piee of information that changes it up.