A watch which gains uniformly is 4 minute slow at 9 A.M. on Sunday ,and is 4 minutes 15 sec ,fast at 9 P.M. on next Friday .when was it correct ?

Question

1- 2 A.M. Thursday 

2- 6 P.M.  Wednesday

3- 1 A.M. Wednesday

4-  6 P.M.

 

Justify and please give solution in easiest way ....

Answer 1

In 132 hours the clock gains 8.25 minutes, or 0.0625 minutes per hour.

To be "on time" the clock must gain 4 minutes.

That takes 64 hours (4 ÷ 0.0625)

 

You figure out when that is. (It is not 4.!)