A train leaves P at 9 am with speed of 30 km/h. Another train leaves Q at 11 am with speed of 45 km/h. The trains are travelling towards each other on parallel tracks. Distance between P and Q is 300 km. When they meet, what is the ratio of distances covered by them?
Show answer & explanation
Correct answer: B
Explanation
Correct Answer is option 2 i.e. 13 : 12
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Understanding |
Application |
Calculation |
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A train leaves P at 9 am with speed of 30 km/h. Another train leaves Q at 11 am with speed of 45 km/h. |
Distance travelled by train 1 till the time train 2 started i.e. in 2 hours = 60 km |
⇒ 2 × 30 = 60 km |
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Distance between P and Q is 300 km. |
Remaining distance = 240 km |
⇒ 300 – 60 = 240
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Since both trains are running in opposite directions. |
Relative speed = 75 km/hr |
⇒ 30 + 45 = 75 |
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Now, this remaining distance is covered by train 1 and 2 both. |
Time in which both the trains will meet = 3.2 hours |
⇒ 240/75 = 3.2 |
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Now, train 1 travelled for 5.2 hours. |
Distance covered by train 1 = 156 km |
⇒ 5.2 × 30 = 156
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Train 2 travelled for 3.2 hours. |
Distance covered by train 2 = 144 km |
⇒ 3.2 × 45 = 144 |
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Required ratio = 13 : 12 |
⇒ 156 : 144 ⇒ 13 : 12 |