Question

Starting from a 130 feet away, a person on a bicycle rides towards a checkpoint and then passes it. The rider is traveling at a constant rate of 25 feet per second. The distance between the bicycle and the checkpoint is given by the equation: d = |130 - 25t|. At what times is the bike 15 feet away from the checkpoint?
a. 4.6 sec and 9.2 sec

b. 2.9 sec and 5.8 sec

c. 4.6 sec and 5.8 sec

d. 2.9 sec and 3.3 sec

Answer 1

For this question you can say d = 15 feet so we need the t then you can say : 
15 = l 130 - 25t l ⇒ because of the absolute value you should say : 
1) 130 - 25t = 15  ⇒ -25t = 15 - 130 ⇒ - 25t = -115 ⇒ t = 115/25 = 4.6 sec 

2) 130 - 25t = - 15 ⇒ -25t = -15 - 130 ⇒ -25t = - 145 ⇒ t = 145/25 = 5.8 sec 
so the answer is c :))
i hope this is helpful 
have a nice day