Speed, Time and Distance
- A and B start running at the same time and from the same point around a circle. If A can complete one round in 40 seconds and B in 50 seconds, how many seconds will they take to reach the starting point simultaneously ?
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Required time = LCM of 40 and 50 seconds
= 200 secondsCorrect Option: B
Required time = LCM of 40 and 50 seconds
= 200 seconds
- Two persons ride towards each other from two places 55 km apart, one riding at 12km/hr and the other at 10 km/hr. In what time will they be 11 km apart?
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Relative speed
= 12 + 10 = 22 kmph
Distance covered
= 55 – 11 = 44 km∴ Required time = 
44 
hours 22
= 2 hoursCorrect Option: C
Relative speed
= 12 + 10 = 22 kmph
Distance covered
= 55 – 11 = 44 km∴ Required time = 44 hours 22
= 2 hours
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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
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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.
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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
-
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?
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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
