A train increases its normal speed by 12.5% and reaches its destinatio

1.	A train increases its normal speed by 12.5% and reaches its destination 20 minutes earlier. What is the actual time taken by the train in the journey? (a) 220 min (b) 180 min (c) 145 min (d) 160 min
Answer» (b) 180 min Let the normal speed of the train be x metres/ minute and the actual time taken by the train in the journey be t minutes. Then, \(x\times{t} = \frac{112.5x}{100}\times(t-20)\) ⇒ \(t = \frac{112.5t}{100}-22.5 ⇒\frac{112.5t}{100}-t=22.5\) ⇒ \(\frac{12.5t}{100}=22.5 ⇒ t = \frac{22.5\times100}{12.5}\) minutes = 180 min.

A train increases its normal speed by 12.5% and reaches its destination 20 minutes earlier. What is the actual time taken by the train in the journey? (a) 220 min (b) 180 min (c) 145 min (d) 160 min

Answer»

(b) 180 min

Let the normal speed of the train be x metres/ minute and the actual time taken by the train in the journey be t minutes. Then,

\(x\times{t} = \frac{112.5x}{100}\times(t-20)\)

⇒ \(t = \frac{112.5t}{100}-22.5 ⇒\frac{112.5t}{100}-t=22.5\)

⇒ \(\frac{12.5t}{100}=22.5 ⇒ t = \frac{22.5\times100}{12.5}\) minutes = 180 min.

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A train increases its normal speed by 12.5% and reaches its destination 20 minutes earlier. What is the actual time taken by the train in the journey? (a) 220 min (b) 180 min (c) 145 min (d) 160 min

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