Given:
The temperature on a mountain peak was 7°F at 6:00 p.m.
By 8:00 p.m., the temperature had dropped to 0°F.
To find:
The temperature at 11:00 p.m. if the temperature continued to drop at about the same rate.
Solution:
Time between 6:00 p.m. to 8:00 p.m. is 2 hours.
Change in temperature in 2 hours is -7°F.
Change in temperature in 1 hours is [tex]-\dfrac{7}{2}^\circ[/tex]F.
Time between 8:00 p.m. to 11:00 p.m. is 3 hours.
Change in temperature in 3 hours is [tex]3\times \dfrac{-7}{2}^\circ[/tex]F, i.e., [tex]-\dfrac{21}{2}^\circ[/tex]F.
Now, the temperature at 11:00 p.m is:
[tex]0-\dfrac{21}{2}=-10.5[/tex]
Therefore, the temperature at 11:00 p.m. is -10.5°F.
Note: All options are incorrect.
