On a certain road 10% of the motorists exceed the posted speed limit and receive speeding tickets, but 20% 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?
Choose one:
A) 10.5%
B) 12.5%
C) 15%
D) 22%
E) 30%
Say there are 100 motorists.   {# of motorists who exceed speed &amp; receive tickets} + {# of motorists who exceed speed &amp; don't receive tickets} = {Total # of motorist who exceed speed};   Given: {# of motorists who exceed speed &amp; receive tickets}=10;   Also, if {Total # of motorist who exceed speed}=x, then 0.2x={# of motorists who exceed speed &amp; don't receive tickets};   10+0.2x=x --&gt; x=12.5   Answer: 12.5%.
<result>B</result>
On a certain road 10% of the motorists exceed the posted speed limit and receive speeding tickets, but 20% 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?