Question

Lisa leaves her house for a road trip and drives at a rate of 50 mph. Keisha leaves her house 1 hour later and drives along the same route at a rate of 60 mph. At any given time t, the distance traveled can be calculated using the formula d = rt, where d represents distance and r represents rate. Which system of equations can be used to find how long after Lisa departs her house she is passed by Keisha?

A) d=50t
d=60t-1

B) d=50t
d=60(t-1)

C) d=50t
d=59t

D) d=50(t-1)
d=60t

Answer 1

B) d = 50t; d = 60(t - 1)
If the time t is in hours, and starts when Lisa leaves her house, then the total time she travels is t; while Keisha travels 1 hour less than the total time, (t - 1)