if it takes 1 second to place a grain of rice on the chessboard, how long will it take to place all the grains on the chessboard for each reward?

Question

example: Reward A had 3768 grains
Reward B had 73628 grains
Reward C had 82613 grains

what is the formula to follow ?
and how should i answer it ?

Answer 1

3768 grains mean 3768*1 second=3768 seconds.

Convert to hours, minutes and seconds:
3768 seconds / 60 s/min.
=62 minutes 48 seconds
= 1 hour 2 minutes 48 seconds.

The other rewards may be worked out in a similar way.