Question

Emily's lawn grows at a constant rate. The height of her lawn, during a 10-day period, is represented by the graph below.

The graph titled 'Emily's Lawn growth' shows 'Days since mowing' from 0 to 10 along the x axis and 'height of grass in centimeters’ from 0 to 10 along the y-axis. A solid line starts from (0, 4) and passes through (2, 5), and (4, 6).

Based on the graph, after how many days will the lawn be 12 centimeters in height?

A.
16 days

B.
8 days

C.
10 days

D.
24 days

Answer 1

Slope = (5−4)/(2−0) = 0.5 cm/day, so height = 4 + 0.5·days.
Set 12 = 4 + 0.5·days → 0.5·days = 8 → days = 16.

Answer: A. 16 days.