In a race of 100 m, A beats B by 20 m or 5 seconds. Find the time taken by A to complete the race and the speed of B.Marks : 2Negative Marks : 0Answer here4 s, 20 m/s20 s, 4 m/s20 s, 25 m/s25 s, 20 m/s

The problem states that A beats B by 20 meters or 5 seconds in a 100 meter race. This means that when A has run 100 meters, B has run only 80 meters. It also means that B takes 5 seconds longer to run 100 meters than A does.

1. First, let's find the time taken by A to complete the race. We know that B takes 5 seconds longer to run 100 meters than A does. So, if we subtract these 5 seconds from the total time B takes to run 100 meters, we will get the time taken by A. But we don't know the total time B takes to run 100 meters. However, we know that B runs 80 meters in the same time that A runs 100 meters. So, the time taken by B to run 80 meters is the same as the time taken by A to run 100 meters. Therefore, the time taken by A to run 100 meters is the same as the time taken by B to run 80 meters, which is 5 seconds less than the time taken by B to run 100 meters. So, the time taken by A to complete the race is 20 seconds.

2. Now, let's find the speed of B. We know that speed is distance divided by time. B runs 80 meters in the same time that A runs 100 meters, which is 20 seconds. So, the speed of B is 80 meters divided by 20 seconds, which is 4 meters per second.

So, the time taken by A to complete the race is 20 seconds and the speed of B is 4 meters per second. Therefore, the correct answer is "20 s, 4 m/s".