itisSheldon wrote:

Before Race R,which is 1,500 meters, Peter's best time in swimming was 21 minutes. Did Peter beat this time in Race R ?

1) Peter took between 0.3 and 0.4 hours to swim 1,500 meters in Race R.

2) Peter took between 1,200 and 1,300 seconds to swim 1,500 meters in Race R.

21 minutes in hours is equal to = 21/60 or 7/20 or 0.35 hours

21 minutes in seconds is equal to = 21*60 = 1260 seconds

We need to know whether peter finished this race R in less than 21 minutes, or in less than 0.35 hours, or in less than 1260 seconds - or not?

(1) Between 0.3 and 0.4 hours, but this could be above or below 0.35. Not sufficient.

(2) Between 1200 and 1300 seconds, but this could be above or below 1260. Not sufficient.

Combining the statements, 0.3 hours is 0.3*3600 = 1080 seconds and 0.4 hours = 0.4*3600 = 1440 seconds. So as per the first statement, his race time is between 1080 and 1440 seconds and as per the second statement, his race time is between 1200 and 1300 seconds. This tells us that the common time value from both statements is between 1200 and 1300 seconds only. Still not sufficient to know whether its less or more or equal to 1260 seconds.

So

E answer