Speed, Time and Distance

his office 20 minutes late. Then his usual time for walking to his office is :Walking at 3 of his usual speed, a man reaches 4

 1 hour
 30 minutes
 45 minutes
 40 minutes

View Hint View Answer Discuss in Forum
Usual time = x minutes
New time = 4x minutes 3 ∵ Speed ∝ 1 Time
According to the question,4x − x = 20 3 ⇒ x = 20 3
⇒ x = 60 minutes i.e. 1 hour.Correct Option: A
Usual time = x minutes
New time = 4x minutes 3 ∵ Speed ∝ 1 Time
According to the question,4x − x = 20 3 ⇒ x = 20 3
⇒ x = 60 minutes i.e. 1 hour.
 Sarthak completed a marathon in 4 hours and 35 minutes. The marathon consisted of a 10 km run followed by 20 km cycle ride and the remaining distance again a run. He ran the first stage at 6 km/hr and then cycled at 16 km/hr. How much distance did Sarthak cover in total, if his speed in the last run was just half that of his first run?

 5 km.
 35 km.
 40 km.
 45 km.

View Hint View Answer Discuss in Forum
Let the total distance be x km.
Time = Distance Speed
According to the question,10 + 20 + x − 30 = 4 35 6 16 3 60 = 4 7 12 ⇒ 5 + 5 + x − 10 = 55 3 4 3 12 ⇒ x + 5 + 5 − 10 = 55 3 3 4 12 ⇒ x + 20 + 15 − 120 = 55 3 12 12 ⇒ x − 85 = 55 3 12 12 ⇒ x = 85 + 55 = 140 3 12 12 12 ⇒ x = 140 × 3 = 35 km. 12 Correct Option: B
Let the total distance be x km.
Time = Distance Speed
According to the question,10 + 20 + x − 30 = 4 35 6 16 3 60 = 4 7 12 ⇒ 5 + 5 + x − 10 = 55 3 4 3 12 ⇒ x + 5 + 5 − 10 = 55 3 3 4 12 ⇒ x + 20 + 15 − 120 = 55 3 12 12 ⇒ x − 85 = 55 3 12 12 ⇒ x = 85 + 55 = 140 3 12 12 12 ⇒ x = 140 × 3 = 35 km. 12
 Walking at the rate of 4 kmph a man covers certain distance in 2 hrs 45 min. Running at a speed of 16.5 kmph the man will cover the same distance in how many minutes ?

 50 min.
 35 min.
 40 min.
 45 min.

View Hint View Answer Discuss in Forum
2 hours 45 minutes
= 2 + 45 hours 60 = 2 + 3 hours 4 = 11 hours 4
∴ Distance = Speed × Time= 4 × 11 = 11 km. 4
∴ Time taken in covering 11 km at 16.5 kmph= 11 hour 16.5 = 11 × 10 × 60 minutes 165
= 40 minutesCorrect Option: C
2 hours 45 minutes
= 2 + 45 hours 60 = 2 + 3 hours 4 = 11 hours 4
∴ Distance = Speed × Time= 4 × 11 = 11 km. 4
∴ Time taken in covering 11 km at 16.5 kmph= 11 hour 16.5 = 11 × 10 × 60 minutes 165
= 40 minutes
 A is twice as fast as B, and B is thrice as fast as C is. The journey covered by
C in 1 1 hours will be covered by A in 2

 15 minutes
 30 minutes
 1 hour
 10 minutes

View Hint View Answer Discuss in Forum
Time taken by C = t hours
∴ Time taken by B = t hours 3 and time taken by A = t hours 6 Here, t = 3 hours 2 ∴ Required time taken by A = 3 hour 2 6 = 1 hour 4 = 1 × 60 minutes 4
= 15 minutesCorrect Option: A
Time taken by C = t hours
∴ Time taken by B = t hours 3 and time taken by A = t hours 6 Here, t = 3 hours 2 ∴ Required time taken by A = 3 hour 2 6 = 1 hour 4 = 1 × 60 minutes 4
= 15 minutes
 A jeep is chasing a car which is 5km ahead. Their respective speed are 90 km/hr and 75 km/hr. After how many minutes will the jeep catch the car ?

 18 min.
 20 min.
 24 min.
 25 min.

View Hint View Answer Discuss in Forum
Relative speed
= 95 – 75 = 15 kmphRequired time = Distance Relative speed = 5 hours 15 = 5 × 60 minutes 15
= 20 minutesCorrect Option: B
Relative speed
= 95 – 75 = 15 kmphRequired time = Distance Relative speed = 5 hours 15 = 5 × 60 minutes 15
= 20 minutes