In a race of 1 km A beats B by 140m or 14 seconds. Find the time taken by A to run 1 km?

86 sec

Distance = Speed  × Time

A beats B by 140 m in 14 second , that means B covers 140 m in 14 sec . 

Speed of B = \(\frac{140}{14}\) = 10 m/s

Time to cover 1000 m = 100 sec

A beats B by 14 sec means A reach 14 sec early. 

So, time taken by A to cover to cover 1000 m = 100 - 14 = 86 sec .

Time taken by a to complete the race is 86 sec .