Question

In a race of one kilometer, A gives B a start of 100 metres and still wins by 20 seconds. But if A gives Bastart of 25 seconds, B wins by 50 metres. The time

taken by A to run one kilometer is:​

Answer 1

Answer:

Let the time taken by A to run 1000 meters

= x seconds

time taken by B to run 900 metres

= x+20x+20 sec.

Speeds of A and B

=1000x,900x+201000x,900x+20respectively

ATQ,

9501000x−1000900x+20=259501000x−1000900x+20=25

(As B is the winner now)

950x1000−1000(x+20)900=25950x1000−1000(x+20)900=25

19x20−10x+2009=2519x20−10x+2009=25

=171x−200x+4000171x−200x+4000

=25×20×925×20×9

29x=500

x=5002950029 sec