Algebra problem

Question

Robin can ride at an average rate of 25km/h. She sets out to overtake her brother Robert who rides at an average rate of 20kmh. If Robin left 1 hour after Robert how long will it take robin to catch up to Robert.

Answer 1

Robin's speed = 25

Robert's speed = 20

distance = speed times time traveled

d= st = 25(t) = 20(t+1)

25t = 20t +20

5t = 20

t = 20/5 = 4 hours for Robin to catch up to Robert

Robin traveled 4 x 25 = 100 km

Robert traveled 5 x 20 = 100 km

Answer 2

d = rt, and the distances are equal.

25t = 20(t + 1)

Solve for t for your answer. Don't forget to label it!