The temperature of a place at midnight is 11°C. If the temperature drops at the rate of 2°C per hour, after how many hours will the temperature become -5°C?

Given: The temperature of a place at midnight is $11°C$. 

The temperature drops at the rate of  $2 °C$ per hour

To do: Find after how many hours will the temperature become $  -5 °C$

Solution:

The temperature has dropped from 11 to -5 degree Celsius.

So total drop = $11 - (-5)$

                        = $16°$ degrees

Time taken for 2 degree drop = 1 hour

=> Time taken for 1 degree drop = $\frac{1}{2}$ hour

=> Time taken for 16 degree drop = $16 \times \frac{1}{2}$

                                                              = 8 hours