Bob finishes the first half of an exam in one-seventh the time it takes him to finish the second half. If the whole exam takes him an hour, how many minutes does he spend on the first half of the exam?
Choose the correct option:
A) 15
B) 24
C) 27
D) 36
E) 40
Many times, it is easiest to think of problems like this conceptually (as opposed to formulaically). Conceptually, if the first half of the exam takes 1/7's the time of the second half (7/7's), we can see that the hour the entire exam took to finish can be broken down into fifth's. (Another way to look at this problem is via ratio's - first half is 1:8 and the second half is 7:8). With each eighth of an hour being 7.5 minutes (60/8), the first half of the exam would have taken 15 minutes. Correct answer is 15.
<result>A</result>
Bob finishes the first half of an exam in one-seventh the time it takes him to finish the second half. If the whole exam takes him an hour, how many minutes does he spend on the first half of the exam?