Bob wants to run a mile in the same time as his sister. If Bob’s time for a mile is currently 11 minutes 20 seconds and his sister’s time is currently 9 minutes 36 seconds, by what percent does Bob need to improve his time in order run a mile in the same time as his sister?	Choose the correct choice from the following
A) 3%
B) 5%
C) 8%
D) 10%
E) 15%
Bob's time = 680 secs.   His sis' time = 576 secs.   Percent increase needed = (680-576/680) * 100 = 104/640 * 100 = 15%. Ans (15%).
<result>E</result>
Bob wants to run a mile in the same time as his sister. If Bob’s time for a mile is currently 11 minutes 20 seconds and his sister’s time is currently 9 minutes 36 seconds, by what percent does Bob need to improve his time in order run a mile in the same time as his sister?