Asif123 wrote:
On a 20-mile course Pat bicycled at an average rate of 30 miles per hour for the first 12 minutes and, without a break, ran the rest of the distance at an average rate of 8 miles per hour. How many minutes did Pat take to cover the entire course?
(A) 75 (B) 105 (C) 117 (D) 150 (E) 162
From the information above one can quickly come up with the following equation (basic equation of Rate*Time = Distance):
30*12/60 + 8t = 20, where t is the time it tool Pat to ran the rest of the distance.
From that we get t = 14/8 = 7/4
Total time the is equal to 7/4 + 12/60 = 39/20 hours or 39*60/20 = 117 minutes