A and B take part in 100 m race. A runs at 5 kmph. A gives B a start of 8 m and still beats him by 8 seconds. The speed of B is:
Question
A and B take part in 100 m race.
A runs at 5 km/h. A gives B a start of 8 m and still beats him by 8 seconds. The speed of B is:
Solution
Step 1: Convert the speed of A from km/hr to m/s. We know that 1 km/hr = 5/18 m/s. So, A's speed = 5*(5/18) = 25/18 m/s.
Step 2: Calculate the time taken by A to cover 100m. Time = Distance/Speed = 100/(25/18) = 72 seconds.
Step 3: Since A beats B by 8 seconds, the time taken by B to run 100m - 8m = 92m is 72 + 8 = 80 seconds.
Step 4: Now, we can find the speed of B. Speed = Distance/Time = 92/80 = 1.15 m/s.
Step 5: Convert the speed of B from m/s to km/hr. We know that 1 m/s = 18/5 km/hr. So, B's speed = 1.15*(18/5) = 4.14 km/hr.
So, the speed of B is approximately 4.14 km/hr.
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