Question

The temperature falls from 0 degrees to -12 1/4 degrees in 3 1/2 hours. Which expression finds the change in temperature per hour?

Answer 1

-7/2 degrees per hour

Explanation:

Divide the total change (-12 1/4 degrees) by the total time elapsed (3 1/2 hrs):

-49/4 degrees -49(2)

------------------------ = ------------- = -7/2 degrees per hour

7/2 hrs 4(7)

Answer 2

Change in temperature per hour = 3.5°C/hr

Explanation:

The temperature falls from 0 degrees to -12 1/4 degrees in 3 1/2 hours.

Change in temperature,

`\Delta T=0-\left ( -12(1)/(4)\right )=0+(12* 4+1)/(4)=(49)/(4)`

Time taken

`t=3(1)/(2)=(3* 2+1)/(2)=(7)/(2)hours`

`\texttt{Change in temperature per hour}=(\Delta T)/(t)=((49)/(4))/((7)/(2))=(98)/(28)\\\\\texttt{Change in temperature per hour}=(49)/(14)=(7)/(2)=3.5^0C/hr`

Change in temperature per hour = 3.5°C/hr