danielwaugh
Jane walked for 4 miles. What was her average speed for the first 2 miles?
(1) Jane's average speed for the 4 miles was 3.2 miles per hour.
(2) It took Jane 15 minutes longer to walk the second 2 miles than it took her to walk the first 2 miles.
The official answer is C.
However, from my readings, i have learned that stopovers can mess up DS speed problems. EX Jane could have had a 5 minute stopover or a 10 minute stopover. And I believe that the answer should be E.
Also, I have read that a test-taker must not assume anything for DS. So, I must not assume that there was no stopover. Or should I say that I cannot assume that there was a stopover? Please help!
I am new to this site, so thank you in advance for the help.
Dan
Given: Jane walked for 4 miles.
Asked: What was her average speed for the first 2 miles?
(1) Jane's average speed for the 4 miles was 3.2 miles per hour.
Total time taken = 4/3.2 = 1.25 hours = 1 hours 15 minutes
No information is provided for first 2 miles
NOT SUFFICIENT
(2) It took Jane 15 minutes longer to walk the second 2 miles than it took her to walk the first 2 miles.
Since total travel time is not provided
NOT SUFFICIENT
Combining (1) & (2)
(1) Jane's average speed for the 4 miles was 3.2 miles per hour.
(2) It took Jane 15 minutes longer to walk the second 2 miles than it took her to walk the first 2 miles.
Total time taken = 4/3.2 = 1.25 hours = 1 hours 15 minutes
Total time = 1.25 hours
x + x + .25 = 1.25
x =.5 hours = 30 minutes
Time taken to cover first 2 miles = x + .25 = .75 hours
Jane's average speed for the first 2 miles = 2 miles / .75 hours = 2.67 miles/hour
SUFFICIENT
IMO C