Question

The temperature, t, in Burrtown starts at 21°F at midnight, when h = 0. For the next few hours, the temperature drops 4 degrees every hour. Which equation represents the temperature, t, at hour h?

A. t = 21h + 4

B. t = 4h + 21

C. t = –4h + 21

D. t = –21h + 4

Answer 1

The Answer to your question is C.

Answer 2

C. t = –4h + 21

Explanation:

We know that when h = 0, t = 21°F. Replacing h = 0 in equation A and D we get:

A.

t = 21h + 4

t = 21(0) + 4

t = 4

D.

t = –21h + 4

t = –21(0) + 4

t = 4

So, none of them are correct.

The temperature drops 4 degrees every hour, this means that for h = 1 then t = 21 - 4 = 17. Replacing h = 1 in equation B and C we get:

B.

t = 4h + 21

t = 4(1) + 21

t = 25

C.

t = –4h + 21

t = –4(1) + 21

t = 17

In consequence, C is the correct option.