Question

I undstood the sol but i cang understand from where time gain in 2s = 0.2/100s is written pls tell me ...

Answer 1

You understood the solution haina till where they have written that t=2-0.2/100 sec haina then you can see that actual time period of pendulum clock is 2 sec and when contraction is there by 0.2%then time comes to be 0.2/100sec less than 2 which means that in actual time there is gain of 0.2/100 sec so there will 0.2/100*24*60*60/2=86.4 i hope it helps you