Question

a swimmer swim in a 90 m long pool . he covers a distance of 180 m by swimming from 1 side end to the another back along the same path .if he cover the first 90 m at a speed of 2 m second ,then how fast should he swim so that his average speed is 3 m second

Answer 1

hy                                            

friend                                    

       here is your answer°°°°

                                                       

→ The pool Length is = 90m

→ Speed to cover first 90 m = 2 m/s

                                                                                                                                   

Speed = distance / time

Time  = distance / speed

Time taken to cover first 90 m

= 90 / 2

= 45 sec

Time taken to travel the next 90 m back = t₂

→Total distance

= 180 m

Therefore

Total time to cover

180 m = 45 + t₂

Average speed to travel

180 m = 3 m/s

       or

            Average speed

= Total distance covered / Total time taken

3 m/s = 180 / 45 + t₂

By cross multiplication

we get the following result 3 x (45 +t₂) = 180 or t2= 15

                        hence                  

time taken to travel back 90 m = 15 sec

To cover his average speed is 3m/s ?

       Speed = distance / time

∴ he must swim with a speed of 6 sec to make

∴ his average speed to be 3 m/s