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?
2 p.m. on Tuesday
2 p.m. on Wednesday
3 p.m. on Thursday
1 p.m. on Friday
Explanation:
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 + 4
4
min.
or
34
min. in 170 hrs.
5 5
Now,
34
min. are gained in 170 hrs.
5
2 min. are gained in 170 x
5
x 2
hrs
= 50 hrs.
34
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.
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 + 4
4
min.
or
34
min. in 170 hrs.
5 5
Now,
34
min. are gained in 170 hrs.
5
2 min. are gained in 170 x
5
x 2
hrs
= 50 hrs.
34
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.