Question

The height (in inches) of a plant after 't' days is (1/2t + 6). After how many days is the plant 21 inches tall? *

Answer 1

Height = 1/2t + 6

To find after how many days the plant is 21 inches tall, replace height by 21:

21 = 1/2t + 6

Solve for t (days)

21-6 = 1/2t

15 = 1/2t

Multiply both sides of the equation by 2:

15(2) = 1/2t (2)

30 =t

After 30 days