A text book is left overnight in the trunk of a car during w

A text book is left overnight in the trunk of a car during winter, and it reaches a temperature of 10^0 F. The book is then brought in to a room that is at 72 ^0 F, and after ten minutes the book has reached a temperature of 40^0 F. What was the book\'s temperature 1 hour after it was brought into the room?

Solution

Temperature of the book before entering the room was 10^0 F.

After the book in brought in the room, it reached a temperature of 40^0 F in 10 minutes i.e. in 120 seconds.

This means book\'s temperature changed from 10^0 F to 40^0 F in 10 minutes.

This implies it changed by 30^0 F in 10 minutes.

We have to find out how much it changed in 1 hour which is equal to 60 minutes.

We can solve it by making a simple method:

Temperature changed in 1 hr or 60 minutes = 30 *60/10 = 180^0 F

Therefore, book\'s temperature 1 hour after it was brought into the room was 180^0 F.