Question
A man reaches his office 10 minutes late at his usual speed, how much time does he usually take to cover this distance ?
30 minute
35 minute
45 minute
40 minute
Solution
Correct
option
is 30 minute
Since he moves at $\dfrac34$ of his speed
So $\dfrac43$ will take time
So $\dfrac43 x-x=10$
$x=30$ min
Question
A person goes to his office at a speed of 60 km/d0 and is returned at a speed of 40 km/do. Find the distance if it takes 5 hour ?
225
224
251
220
Solution
Correct
option
is 224
From the formula $ =\dfrac{xy}{x+y}\times t$
we are able to calculate half the distance so $=\dfrac{24\times21}{24+21}\times10=112$
so the full distance $= 2\times112=224$ km
Question
A train 150 m long takes 30 seconds to cross a bridge 500 m long. How much time will this train take to cross a platform 370 meters long?
36 seconds
30 seconds
24 seconds
18 seconds
Solution
Correct
option
is 24 seconds
Speed of train =$\dfrac {150 + 500}{30}= \dfrac {650}{30}=\dfrac {65}3$m/second
Required time =distance /time =$\left (\dfrac{150 +370}{65}\right)\times3= 24$ seconds
Question
A car covers 80 km in 2 hours. and a train travels 180 km in 3 hours. What is the ratio of the speed of the car to that of the train?
2 : 3
3 : 2
3 : 4
4 : 3
Solution
Correct
option
is 2 : 3
Speed = distance / time
$\therefore$ Speed of car : Speed of train
=$ \dfrac {80 }2 :\dfrac {180 }3 = 40 : 60 = 2 : 3 $
Question
A bullock cart has to cover 120 distances in 15 hours. If it completes half the journey in $\dfrac 35$ time, then at what speed will the bullock cart have to be driven to complete the remaining journey in the remaining time?
6.4 km/h
6.67 km/h
10 km/h
15 km/h
Solution
Correct
option
is 10 km/h
Remaining time $\dfrac 25 \times 15 =6 $hours
Required speed = $\dfrac {60 }6 = 10 $ kmph