Question

A watch which gains uniformly is 2 min slow at noon on Monday and is 4 min 48s fast at 2 pm on the following Monday.When was it correct ?

• A. 2 pm on Tuesday
• B. 2 pm on Wednesday
• C. 3 pm on Thursday
• D. 1 pm on Friday

Answer 1

Answer: (B)

2 pm on Wednesday

Time from 12 pm on Monday to 2 pm on the following Monday = 7 days 2 h
So, the watch gains = $2+4\frac{48}{60}min$
$=6\frac{4}{5}min$
$\frac{34}{5}min$ are gained in 170 h.
$\therefore$2 min are gained in $70\times \frac{5}{34}\times 2$
=50 h =2 days 2 hours
So watch is correct 2 days 2 h after 12 pm on Monday i.e.It will be correct at 2 pm on Wednesday.