When Emily woke up, the temperature was 8°F. By noon, the temperature had risen by 3°F. It rose another 6°F in the afternoon to reach the day’s high temperature. By the time Emily went to bed, the temperature had dropped 21°F from the high temperature. What was the temperature when Emily went to bed?

The temperature when Emily went to bed was -4°F.

Step-by-step explanation:

8°F + 3°F = 11°F (noon)

The temperature had risen by 3°F by noon. This means to add 3.

noon + 6°F = the day's high temperature

11°F + 6°F = 17°F (the day's high temperature)

The temperature rose another 6°F in the afternoon. This means add 6 to the temperature from noon.

high temperature - 21°F = temperature at bed

17°F - 21°F = -4°F

The temperature dropped by 21°F when Emily went to bed. This means to subtract 21 from the day's high temperature.  

Risen, rose, and increase mean addition.

Decrease, dropped, and decline mean subtraction.

Hope this helps :)

The student did not distribute properly to get A = P + Prt.

The equation can be fixed by putting a factor of P in the denominator: r = (A - P) / (Pt)

I just took this part of the lesson. Good luck to all!