Edwin is planning to drive from Boston to New Orleans. By what percent would his travel time be reduced if Edwin decides to split the driving time equally with his friend George, instead of making the trip alone?

(1) The driving distance from Boston to New Orleans is 1500 miles.
(2) George’s driving speed is 1.5 times Edwin’s driving speed.


Statement 1 : Does not tell us either Edwin'speed or George's. Hence we cannot calculate time taken in any scenario. INSUFFICIENT

Statement 2 : Let distance be d

Time taken originally = d/s

Now in second scenario Edwin drives k miles and George drives d-k miles

Therefore time taken = k/s + d-k/(1.5s)

k/s = (d-k) / (1.5)s ... Given

d=2.5k

Therefore original time taken = 2.5k /s

New time taken = k/s + (1.5k/1.5s)

= (2k)/s

Reduction is 0.5 k/s

Therefore percent reduction is 20%

SUFFICIENT
_________________

I got this question on Mgmat too.
Time was less so i just did it very fast.
A- We have to see the time but only distance given. Cant take any thing out of it. So A and D gone.
B- Driving speed relation given and we know from question stem time is split equally. Bingo Time and speed relation can be established and there by the reduced time percent.
So answer is B

rishi02 - You are taking both Edwin and George's time into consideration while calculating the reduction, whereas only Edwin's Driving time reduction is asked. Earlier Edwin was taking 2.5k/s time alone for driving and after taking help from George, his driving time has reduced to k/s. So, percentage of Edwin's driving time reduction can be calculated.
_________________

Statement 1 : Does not tell us either Edwin'speed or George's. Hence we cannot calculate time taken in any scenario. INSUFFICIENT
Statement 2: Tells us the speed rate of edwin and george.
It's already given that both of them drove for an equal amount of time , so u can find the % amount of time reduced irrespective of the distances because of the reasons provided.

So, statement 2 alone is sufficient