Question

6. To save fuel, to avoid air pollution and for good health two persons A and B
ride bicycle for a distance of 12 km to reach their office. As the cycling
speed of B is 2 km/h more than that of A, B takes 30 minutes less than
that of A to reach the office. Find the time taken by A and B to reach the
office.

please tell me the time taken​

Answer 1

Explanation: : Difference in timing = 15 – (–20) = 35 min. Let required distance = x.

∴ x/10 - x15 = 35/60 → x = 17.5 km.

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Description for Correct answer:

Time = DistanceSpeed

As per first condition, d10=t+660=d=10t+1 ......(i)

As per second condition, d12=t−660=12t−65 .... (ii)

From Eqs. (i) and (ii), we have

10t+1=12t−65

2t=1+65=115=t=1110

Therefore, From E (i), d=10×1110+1

d = 11 + 1 = 12

d = 12 km