EduGoog

A watch which gains uniformly is 2 minutes low at noon on Monday and is 4 min. 48 sec fast at 2 p.m. on the following Monday. When was it correct?

Option:
A. 2 p.m. on Wednesday
B. 1 p.m on friday
C. 12 p.m on thursday
D. 9 a.m on saturday
Answer: A . 2 p.m. on Wednesday

Justification:

Time from 12 p.m. on Monday to 2 p.m. on the following Monday = 7 days 2 hours = 170 hours. 

 The Watch gains 2+445">(2+445)

 min.  or 345">345

  min.in 170 hrs. 

Now,  345">345

min.are gained in 170 hrs. 

  2 min.are gained in170*534*2">(170*534*2)

 hrs=50 hrs 

 Watch is correct 2 days 2 hrs. after 12 p.m. on Monday i.e., it will be correct at 2 p.m. on Wednesday

Next