Question

7. A watch is getting slow by 3 minutes for each hour in a day. If it shows 8 a.m. now, what will be the
time after 12 hours?​

Answer 1

Step-by-step explanation:

It takes 24×2+12=60 hours from 1 pm of Tuesday to 1 am of Friday i.e. 60×60=3600 minutes.

So, in real 3600 minutes it counts 3600+1+2=3603 minutes(1 minute slow at 1 pm on Tuesday and 2 minutes fast at 1 am on Friday).

So, in one real minute it counts 3603/3600=1.0008333 minutes.

Suppose, after x minutes from 1 pm on Tuesday, it'll show the correct time.

Then, real x minutes=(x+1) minutes in the given watch.

⟹ 1 minute=(x+1)/x minutes in the given watch.

⟹ (x+1)/x=1.0008333

⟹ x+1=1.0008333x

⟹ x=1/0.0008333=1200.048 min =20.0008 hrs

∴ 1 pm on Tuesday + 20 hrs = 9 am on Wednesday.

Hence, the watch will show correct time at 9:00 am on Wednesday.

Answer 2

Step-by-step explanation:

hope it helps you