Given :
Cathy lives in a state where speeders are fined $15 for each mile per hour over the speed limit.
Cathy was given a ticket for $105 for speeding on a road where the speed limit is 60 miles per hour.
To Find :
How fast was Cathy driving.
Solution :
Let, speed of Cathy is v miles per hour.
Number of miles per hour over the speed limit, n = v - 60 miles per hour.
It is given that speeders are fined $15 for each mile per hour over the speed limit.
So, total amount of fine for Cathy is :
105 = 15×( v - 60 )
v-60 = 7
v = 67 miles per hour
Therefore, Cathy was driving with speed of 67 miles per hour.
