Bob wants to run a mile in the same time as his sister. If Bob’s time for a mile is currently 10 minutes 40 seconds and his sister’s time is currently 5 minutes 20 seconds, by what percent does Bob need to improve his time in order run a mile in the same time as his sister?	Select the correct option:  A) 3%  B) 50%  C) 8%  D) 10%  E) 12%
Bob's time = 640 secs.   His sis' time = 320 secs.   Percent increase needed = (640-320/640) * 100 = 320/640 * 100= 
<gadget id="calculator">320/640 * 100</gadget>
<output>50</output>
50%. Ans (50%).
<result>B</result>
Bob wants to run a mile in the same time as his sister. If Bob’s time for a mile is currently 10 minutes 40 seconds and his sister’s time is currently 5 minutes 20 seconds, by what percent does Bob need to improve his time in order run a mile in the same time as his sister?