John drives 50 miles to work each day and returns by the same

Question

John drives 50 miles to work each day and returns by the same route in the evening. He is able to drive only 25 miles per hour during rush hour in the morning. He decides to come home early and take advantage of the light traffic in the early afternoon. He makes it back home in half the usual rush-hour time. What is his average speed to and from work that day?

(A) 25 mph
(B) 30 1⁄3 mph
(C) 33 1⁄3 mph
(D) 37.5 mph
(E) 50 mph

(A) 25 mph
(B) 30 1⁄3 mph
(C) 33 1⁄3 mph
(D) 37.5 mph
(E) 50 mph

BrentGMATPrepNow · Answer

John drives 50 miles to work each day and returns by the same route in the evening. He is able to drive only 25 miles per hour during rush hour in the morning.   
Travel time = distance/speed = (50 miles)/(25 miles per hour) = 2 hours
In other words, John's RUSH HOUR driving time =  2 hours

He makes it back home in half the usual rush-hour time   
Half of  2 hours  =  1 hour 
So, John's RETURN TRIP driving time =  1 hour

AVERAGE SPEED = TOTAL DISTANCE/TOTAL TIME
= (50 + 50)/( 2 hours  +  1 hour )
= 100/3
= 33 1/3 miles per hours

Answer:  C

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sashiim20 · Answer

Let the Distance from home to work be D. (Distance from work to home is also D as its same distance.)
Total Distance traveled = D + D = 2D

John drives at a speed of 25 miles/hr during rush hour in the morning from home to work.
Time traveled from home to work = Distance / Speed =  \frac{D}{25}

John returns home in half the usual rush hour time. Speed would be his normal speed = 50 miles/hr
Time traveled from work to home =  \frac{D}{50}

Total Time traveled =  \frac{D}{25} + \frac{D}{50}  =  \frac{2D + D}{50}  =  \frac{3D}{50}

Average speed = Total Distance / Total Time =  \frac{2D}{(3D/50)}  =  \frac{2 *50}{3}  =  \frac{100}{3}  = 33 \frac{1}{3}  mph
Answer C...

Kinshook · Answer

Given: 
1. John drives 50 miles to work each day and returns by the same route in the evening. 
2. He is able to drive only 25 miles per hour during rush hour in the morning. 
3. He decides to come home early and take advantage of the light traffic in the early afternoon. 
4. He makes it back home in half the usual rush-hour time. 
Asked: What is his average speed to and from work that day?

Total distance to and from work = 50 + 50 = 100 miles

Total time taken = 50/25 + 50/25*2 = 2 + 1 = 3 hours

Average speed to and from work that day = 100 /3 = 33 1/3 mph

IMO C

John drives 50 miles to work each day and returns by the same

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John drives 50 miles to work each day and returns by the same

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