To find the times when she is 90 ft away from you, we set the distance formula equal to 90 and solve for t:
|150 - 20t| = 90
Since the absolute value function can be positive or negative, we have two cases to consider:
Case 1: 150 - 20t = 90
Solving for t, we get:
-20t = -60
t = 3
Case 2: 150 - 20t = -90
Solving for t, we get:
-20t = -240
t = 12
Therefore, she is 90 ft away from you at t = 3 seconds and t = 12 seconds.
She is 90 ft away from you after 3 s and 12 s.
Starting from 150 ft away, your friend skates toward you and then passes you. She skates at a constant speed of 20ft/s. Her distance d from you in feet after t seconds is given by d = |150 - 20t|. At what times is she 90 ft from you?
She is 90 ft away from you after [ ] s.
1 answer