John and Jacob set out together on bicycle traveling at 15 and 9 miles per hour, respectively. After 40 minutes, John stops to fix a flat tire. If it takes John one hour to fix the flat tire and Jacob continues to ride during this time, how many hours will it take John to catch up to Jacob assuming he resumes his ride at 15 miles per hour? (consider John's deceleration/acceleration before/after the flat to be negligible)
Options:
A) 3 B) 3 1/3 C) 3 1/2 D) 4 E) 1 1/4
John's speed - 15 miles/hr   Jacob's speed - 9 miles/hr   After 40min (i.e 2/3hr), distance covered by John = 15x2/3 = 10 miles.   Jacob continues to ride for a total of 1hour and 40min (until John's bike is repaired). Distance covered in 1 hour 40min (i.e 5/3hr) = 9x5/3 = 15 miles.   Now, when John starts riding back, the distance between them is 7.5 miles. Jacob and John are moving in the same direction.For John to catch Jacob, the effective relative speed will be   15-9= 
<gadget id="calculator">  15-9</gadget>
<output>6</output>
6 miles/hr.   Thus, to cover 7.5 miles at 6 miles/hr, John will take  7.5/6= 
<gadget id="calculator"> 7.5/6</gadget>
<output>1.25</output>
1.25 hours   Answer 1 1/4
<result>E</result>
John and Jacob set out together on bicycle traveling at 15 and 9 miles per hour, respectively. After 40 minutes, John stops to fix a flat tire. If it takes John one hour to fix the flat tire and Jacob continues to ride during this time, how many hours will it take John to catch up to Jacob assuming he resumes his ride at 15 miles per hour? (consider John's deceleration/acceleration before/after the flat to be negligible)