Question

A swimmer swims 90m long pool. He covers the distance of 180m by swimming from

one end to other end back along the same path. If he covers the first 90m at speed of 2m/s,

then how fast he swim so that his average speed is 3m/s​

Answer 1

Answer:

Total Pool distance=90m

Total Distance=180m

Speed in first round 90m =2m/s

Let speed in second one=x

Average speed=3m/s

t1=distance/speed , i.e 90/2=45 seconds

t2=90/x

now equate the whole equation

Average speed = Total Distance /Total Time taken

=3=180/45+90/x

=3= 180x/45+90=3=180x/135

=3×135=180x

405=180x

405/180=x

2.25

Explanation:

You can use it perfectly ...I have explained it in the solution