Question

4. Angelica measured the temperature outside her house each day for a month. She found that on the first day of the month, the temperature was 90°F, and it decreased by 3°F each day. Which equation represents t, the temperature outside Angelica's house, on a certain day of the month, d?
t = 90 - 3d
t = 90 + 3d
t = 90 + 3(d - 1)
t = 90 - 3(d - 1)