A person driving at the speed of 40 km/hr reaches office 1 minute early while he reaches 3 minutes late if driving at 36 km/hr. What is the distance (in km) that she is covering?

Question

Question

This question was previously asked in

RRB ALP CBT I 17 Aug 2018 Shift 2 Official Paper

Answer 1

Given:

The person driving at the speed of 40 km/hr reaches office 1 minute early while he reaches 3 minutes late if driving at 36 km/hr.

Concept used:

1. 1 min = 60 seconds

2. Distance = Speed × Time

3. 1m/s = 18/5 km/h

4. 1 km = 1000 m

Calculation:

40 km/h = 40 × 5/18 = 100/9 m/s

36 km/h = 36 × 5/18 = 10 m/s

3 minutes = 180 seconds

Let the distance be D meters.

According to the question,

\(\frac {D}{10} - \frac {D}{\frac {100}{9}} = 180 + 60 \)

⇒ \(\frac {D}{10} - \frac {9D}{100} = 240\)

⇒ \(\frac {D}{100} = 240 \)

⇒ D = 24000

Now, the distance = 24000 ÷ 1000 = 24 km

∴ The distance that she is covering is 24 km.

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