Home » Aptitude » Speed, Time and Distance » Question
  1. In a one-kilometre race, A beats B by 15 seconds and B beats C by 15 seconds. If C is 100 metres away from the finishing mark, when B has reached it, find the speed of A.
    1. 9.5 m/sec.
    2. 9 m/sec.
    3. 8 m/sec.
    4. 8.3 m/sec
Correct Option: D

Let B take x seconds to run 1000 m.
∴  Time taken by C
= (x + 15) seconds

∴ 
x
=
900
=
9
x + 15100010

⇒  10x = 9x + 135
⇒  x = 135 seconds
Now in a one kilometre race, A beats B by 15 seconds.
It means A covers 1000 m in
135 – 15 = 120 seconds
∴  Speed of A =
1000
=
25
m/sec
1203

= 8.3 m/sec.



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