The temperature at 12 noon was 10*C above zero . If it decrease at the rate of 2*C/hr until midnight , at what waht time would the temperature be 8*C below zero . What would be the temperature

Given: The temperature at 12 noon was 10*C above zero . Tt decrease at the rate of 2*C/hr until midnight 

To find: What  time would the temperature be 8*C below zero 

Solution:

At 12 noon, the temperature is 10 * C

The temperature decreases at the rate of 2* C per hour till midnight

At 1 pm the temp would be 10 - 1 $\times$x2 = 8 * C

At 2 pm the temp would be 10 - 2 $\times$x 2 = 10 - 4 = 6 * C

at T pm the temp would be 10 - 2 $\times$T = -8* C 

or 2T = 10 + 8 = 18 or T = 9 pm Answer

At midnight  T = 12, so the temp would be $10 - 2T = 10 - 2 \times 12$

                                                                                               = $10 - 24 = -14$ * C