Starting from 150 ft away, your friend skates toward you and then passes you. She skates at a constant speed of 20 ft/s. Her distance d from you in feet after t seconds is given by d=l 150 -20t l At what times is she 90 ft from you?

Question

Starting from 150 ft​ away, your friend skates toward you and then passes you. She skates at a constant speed of 20 ​ft/s. Her distance d from you in feet after t seconds is given by d=l 150 -20t l At what times is she 90 ft from​ you?

GPT 3.5 · Answer

To find the times at which your friend is 90 ft away from you, we need to solve the equation d = 90.

Substituting d = 90 into the given equation, we have:

|150 - 20t| = 90

Since the distance cannot be negative, we can drop the absolute value signs:

150 - 20t = 90 or 150 - 20t = -90

Solving the first equation, we have:
150 - 20t = 90
-20t = 90 - 150
-20t = -60
t = -60 / -20
t = 3

Solving the second equation:
150 - 20t = -90
-20t = -90 - 150
-20t = -240
t = -240 / -20
t = 12

So, your friend is 90 ft away from you at t = 3 seconds and t = 12 seconds.

Starting from 150 ft​ away, your friend skates toward you and then passes you. She skates at a constant speed of 20 ​ft/s. Her distance d from you in feet after t seconds is given by d=l 150 -20t l At what times is she 90 ft from​ you?

Starting from 150 ft away, your friend skates toward you and then passes you. She skates at a constant speed of 20 ft/s. Her distance d from you in feet after t seconds is given by d=l 150 -20t l At what times is she 90 ft from you?