Speed, Time and Distance
- A speed of 36 km/hr. is the same as ?
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Speed in m/sec = speed in km/hr x (5 / 18 )
Speed in m/sec = ( 36 x 5/18 ) m/secCorrect Option: A
Speed in m/sec = speed in km/hr x (5 / 18 )
Speed in m/sec = ( 36 x 5/18 ) m/sec
= 10 m/sec
- Rahim covers a certain distance in 14 hrs 40 min. He covers one half of the distance by train at 60 km/hr. and rest half by road at 50 km/hr. The distance travelled by him is ?
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Let the total distance be y km.
Then, (y/2) x (1/60) + (y/2) x (1/50) = 44/3Correct Option: D
Let the total distance be y km.
Then, (y/2) x (1/60) + (y/2) x (1/50) = 44/3
⇒ y/120 + y/100 = 44/3
⇒ 5y + 6y = 8800
⇒ y = 800
∴ Required distance = 800km.
- A car complete a certain journey in 8 hour. It cover half the distance at 40 km/hr and the rest at 60 km/hr, The length of a journey is ?
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Let the length of total journey be y km.
From question
( y/2 x 1/40 ) + ( y/2 x 1/60) = 8Correct Option: C
Let the length of total journey be y km.
From question
( y/2 x 1/40 ) + ( y/2 x 1/60) = 8
⇒ y/80 + y/120 = 8
⇒ 3y + 2y = 1920
∴ y = 384 km.
- A car covers four successive three km stretches at speed of 10 km/hr, 20 km/hr, 30 km/hr and 60 km/hr. respectively. Its average speed over this distance is ?
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Total time taken = (3/10 + 3/20 + 3/30 + 3/60) hrs.
= 3/5 hrs.
Correct Option: B
Total time taken = (3/10 + 3/20 + 3/30 + 3/60) hrs.
= 3/5 hrs.
∴ Average speed = {12 / (3 / 5)} km/hr.
= (12 x 5 ) / 3 km/hr.
= 20 km/hr.
- Two men start together to walk to a certain destination, one at 3.75 km an hour and another at 3 km an hour. The former arrives half an hour before the latter, the distance is ?
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Let the distance be y km.
From question
y/3 - y/3.75 = 1/2Correct Option: C
Let the distance be y km.
From question
y/3 - y/3.75 = 1/2
⇒ (3.75y - 3y) / (3 x 3.75) = 1/2
⇒ 1.5y= 3 x 3.75
∴ y = ( 3 x 3.75 ) / 1.5
= 7.5 km.