An emergency vehicle travels 10 miles at a speed of 50 miles per hour.

Question

An emergency vehicle travels 10 miles at a speed of 50 miles per hour. How fast must the vehicle travel on the return if the round-trip travel time is to be 20 minutes?

A. 55mph

B. 60mph

C. 65mph

D. 70mph

E. 75mph

Archit3110 · Answer

total time taken in onward journet
10*60/50 = 12 mins
total duration of journet= 20 mins
time left= 8 mins
or say 8/60 hrs
so 10 = speed * 8/60
speed = 75 mph
IMO E

ashudhall · Answer

time taken for one side journey = 10/50 hour = 60/5 =12 min
time for return journey should be 8 minutes to complete journey in 10 mins
i.e 2/3 of one side 2/3 of 12 is 8
for time to be 2/3 speed has to be 3/2 of 50 i.e 75
E

ScottTargetTestPrep · Answer

Since it takes 10/50 = 1/5 hr = 12 minutes to travel 10 miles at a speed of 50 mph, the return trip must take 8 minutes = 2/15 hr, in order for the round-trip travel time to be 20 minutes. Therefore, the speed of the return trip must be 10/(2/15) = 10 x 15/2 = 75 mph.

Answer: E

ajdse22 · Answer

This is a good question. The time taken on the first part of the journey is 1/5 of an hour, which is 12 minutes. According to the prompt, the return trip must be done in only 8 minutes. Since the return trip should be 50% faster in order to achieve that. 1.5*50 = 75. That is the answer.

Abhishek009 · Answer

T_1 = \frac{D_1}{S_1}

Or,  T_1 = \frac{10*60}{50} = 12

We, know  T = T_1 + T_2

For,  T_2  , we know,  D = 10  ,  S = ?  and  T = 20  or  T_2 = 8

Or,  8 = \frac{10*60}{S}

Or,  8S = 600

Or,  S = 75  , Answer must be (E)

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

An emergency vehicle travels 10 miles at a speed of 50 miles per hour.

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

An emergency vehicle travels 10 miles at a speed of 50 miles per hour.

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards