Problem Solving

Hi,

The answer is B) but I don't seem to translate word into equation.... Can anyone please help?

Let 'T' be the total no. of motorists on the road.
Let E(R) be the no. of motorists who exceed the speed and receive tickets.
Let E(~R) be the no. of motorists who exceed the speed limit but doesn't receive tickets.
Let 'E' be the no. of motorists who exceed speed.
=> E = E(R) + E(~R)

From statement (1)
-> E(R) = (10/100)* T
From statement (2)
-> E(~R) = (20/100)*E
E(~R) = (20/100)*(E(R) + E(~R))
E(~R) = (1/4)*E(R)

Using both the equations, find out
E(R) + E(~R)/T

Let the total number of motorists on the road be x
Now 10x/100 or x/10 motorists exceed speed limits and also receive tickets
Now out of the total number of people who exceed speed limits (say y)...20% exceed speed limits and do not receive tickets...thus people who do speed and get tickets = 80y/100 or x/10
So 8y/10 = x/10
or y = 10x/80

So % of speed limit offenders = (10x/80)/x * 100
= 1000/80
= 100/8 = 12.5%