Question

The graph represents a system of linear equations comparing the outside and inside temperatures y, in degrees Fahrenheit, recorded at a school one day x hours after 8:00 a.m.

A coordinate grid showing Daily Temperature with Hours after 8:00 a m on the horizontal, x axis and Temperature in degrees Fahrenheit on the vertical, y, axis. One line labeled Inside passes through (0, 70) and (8, 70). The second line passes through (0, 58) and passes through (8, 70).
After how many hours were the inside and outside temperatures equal?

6 hours
7 hours
8 hours
10 hours

Answer 1

The lines meet at (8, 70). Since the inside temperature is 70°F and the outside line reaches 70°F at x = 8, they are equal after 8 hours.