In a race of 1 km A beats B by 170m or 17 seconds. Find the time taken by A to run 1 km?

83 sec

Distance = Speed  × Time

A beats B by 170 m in 17 second , that means B covers 140 m in 14 sec . 

Speed of B = \(\frac{170}{17}\) = 10 m/s

Time to cover 1000 m = 100 sec

A beats B by 17 sec means A reach 17 sec early. 

So, time taken by A to cover to cover 1000 m = 100 - 17 = 83 sec .

Time taken by a to complete the race is 83 sec .