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To travel 432 km, an Express train takes 1 hour more than Duronto. If however, the speed of the Express train is increased by 50%, it takes 2 hours less than Duronto. What is the speed (in km/hr) of Duronto train?
- A60
- B54
- C48
- D72
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0
CCommunity
Let the speed of Duronto train be y km/hr and that of Express train be z km/hr
According to the problem statement
⇒ 432/y + 1 = 432/z
⇒ 1/z = 1/y + 1/432 ----(i)
If speed of Express train increased by 50%, now the speed will be 1.5 z,
Now
⇒ 432/1.5z + 2 = 432/y Using (i)
⇒ 288(1/y + 1/432) + 2 = 432/y
⇒ 288/y + 2/3 + 2 = 432/y
⇒ y = 54 km/hr
∴ the speed of Duronto train is 54 km/hr
According to the problem statement
⇒ 432/y + 1 = 432/z
⇒ 1/z = 1/y + 1/432 ----(i)
If speed of Express train increased by 50%, now the speed will be 1.5 z,
Now
⇒ 432/1.5z + 2 = 432/y Using (i)
⇒ 288(1/y + 1/432) + 2 = 432/y
⇒ 288/y + 2/3 + 2 = 432/y
⇒ y = 54 km/hr
∴ the speed of Duronto train is 54 km/hr
0
CCommunity
Speed reverse time and 6 hour to express train so Toronto 8 hour and speed 54 km /hr