Ramesh and Suresh both ran a 30 mile marathon.Ramesh ran 10 miles at

Question

Ramesh and Suresh both ran a 30 mile marathon.Ramesh ran 10 miles at 10mph and the the remaining 20 miles at 5mph.Suresh ran one third (by time) of the marathon at 10mph and the remaining two thirds at 5mph.Which of the following must be true ?

A)Average speed of Ramesh is greater than average speed of Suresh.
B)Average speed of Suresh is greater than average speed of Ramesh.
C)Average speed of Ramesh is equal to average speed of suresh.
D)Average speed of Ramesh is twice the average speed of Suresh.
E)None of the above.

chetan2u · Answer

Hi

Ramesh..
Time taken is  \frac{10}{10}+\frac{20}{5}=1+4=5hr

Suresh.
Let the time taken be x.
So x/3 is at 10mph, thus distance traveled = 10x/3
And 2x/3 is at 5mph, thus distance traveled = 10x/3..
Total distance=30=10x/3 + 10x/3....
20x/3=30 or  x=\frac{30*3}{20}=4.5hr

Since Suresh takes lesser time, his average speed is greater..

Hence B

old1guy · Answer

Average Speed is always Total Distance Covered/Total Time taken

Since distance is given as 30 We have to determine Total Time for both Ramesh and Suresh

Ramesh 10/10 hr + 20/5 hr = 5 hr
Ramesh Avg Speed = 30/5 = 6 MPH

In case of SURESH lets say total time is T. So we have to find 30/T

It is given T/3 *10 + 2T/3 * 5 = 30
 30/T = 20/3 > 6 MPH

hence SURESH avg speed > Ramesh Avg Speed

warriorguy · Answer

Ramesh => Total time taken=> 5 hours; Distance = 30 miles; Speed = 6 mph

Suresh

D = \(\frac{10}{3}\) * T + \(\frac{10}{3}\) * T

D/T= \(\frac{20}{3}\)

S = \(\frac{20}{3}\)

hence SURESH avg speed > Ramesh Avg Speed

If they both munched on 5-star, it would have been the same :-D

stonecold · Answer

Here is what i did in this question =>

Distance for both Ramesh and Suresh => 30

Ramesh's Case =>

Distance = 30
Time => 10/10 + 20/5 => 5hours.

Hence Average speed of Ramesh => 30/5=> 6mph

Suresh's Case=>

Let the total time be t hours
Hence 10*(t/3) + 5*(2t/3) =30
t=90/20=9/2=4.5 hours

Average speed = 30/4.5=> 300/45=> 100/15=> 20/3=> 6.66666666

Hence Suresh's speed is greater than Ramesh's speed.

SMASH that B.

effatara · Answer

There is a simpler and quicker way of solving this problem through the application of logic which doesn't involve any calculation:
Ramesh took 5 hrs to run the marathon (10/10 + 20/5) of which he ran 1 hr (1/5th of his ttl time) at 10 mph and 4 hrs (4/5th of ttl time) at 5 mph whereas Suresh ran 1/3rd of his ttl time at 10 mph and 2/3rd at 5 mph. The obvious conclusion is that he completed the marathon in less time than Ramesh. T/4, Suresh's average speed is more than Ramesh's. Answer: B

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Ramesh and Suresh both ran a 30 mile marathon.Ramesh ran 10 miles at

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