Maura drives to work in 40 minutes. She takes the same route to return

Question

Maura drives to work in 40 minutes. She takes the same route to return home. If her average speed on the trip home is half as fast as her average speed on her trip to work, how much time does she spend driving on the round trip?

A. 1 hr
B. 1 hr 15 mins
C. 1 hr 20 mins
D. 1 hr 40 mins
E. 2 hrs

A. 1 hr
B. 1 hr 15 mins
C. 1 hr 20 mins
D. 1 hr 40 mins
E. 2 hrs

Archit3110 · Answer

let distance one way be d
and speed from home to work be x
we are given ; d/x = 40 mins
speed towards work ; d/40
and for return speed is half so speed towards home ; d/80
total avg speed ; 2ab/a+b
or say ; 2*d/40*d/80 / ( 3d/80)
solve we get avg speed of journey ; d/120
total time shall be 120 mins or say 2 hours
OPTION E

dimri10 · Answer

40 minutes is 2/3 hour

pick numbers that divide by 3
2/3===6 (v go )===== 4 (D go)

the same=4 (D return)== 3 (V return- 1/2 of 6)===4/3 (T return)

4/3+2/3=6/3 which is 2

Satishqwerty · Answer

When distance is constant, speed is inversely proportional to time. 
Let Distance be D
Speed of work to home(Swh) =  1/2 	imes  Shw
Speed of home to work(Shw) = Distance/Time = D/40

\frac{Shw}{Swh} = \frac{D}{40} / \frac{D}{80}

\frac{Shw}{Swh} = \frac{80}{40}

\frac{Shw}{Swh} = \frac{2}{1}

Now, time will be inversely proportional.

\frac{Thw}{Twh} = \frac{1}{2}

From home to work it takes 40 mins, 
from work to home it will take 80 mins.

Edit: Learning: Cross check the question what it is asking

Total time spend in driving on the round trip = 80 + 40 = 120

OA, E

Kinshook · Answer

Given: 
1. Maura drives to work in 40 minutes. 
2. She takes the same route to return home. 
3. Her average speed on the trip home is half as fast as her average speed on her trip to work
Asked: How much time does she spend driving on the round trip?

Distance = speed * time

s1 * t1 = s2 * t2
s1 * 40 = s1/2 * t2
t2 = 80 mins

Total time = t1 + t2 = 40 + 80 = 120 mins = 2 hours

IMO E

yashikaaggarwal · Answer

One side Distance = D
Speed = S

Time taken by Maura to drive to work from home = 40 minutes=D/S

The return speed is 1/2 of that of speed from home to work 
D/(S/2) = 2D/S = time.
Therefore the time taken by maura to cover 2*Distance with the same speed = time taken by maura to cover Distance work to home = 40*2 = 80 minutes.

Total time taken by Maura = 40+80 = 120 minutes.
1 hour = 60 minutes
120/60 = 2 hours.

Answer is E

Posted from my mobile device

ShreyasJavahar · Answer

Speed is inversely proportional to the time taken.
A (1/2) reduction in the speed would lead to a (2/1) gain in the time which means that the return journey would take 40*2 = 80 minutes.
Total travel time = 40 + 80 = 120 minutes or 2 hours.

kawal27 · Answer

lets take total distance 400 km
and total speed 10 km/hr so time will become 40 min
now same distance but half speed which is 5 km/hr
400/5=80 min
 total=40+80=120 min
ANS:E

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Maura drives to work in 40 minutes. She takes the same route to return

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