distance = rate * time
time = distance / rate
rate = distance / time
*******Distance
****Time
****** Rate
*****
Randy 540
3t r
Andy 135 t r -15
Randy;s Rate=
540 / 3t
Andy's Rate = 135 / t
Andy's rate was 15 mph slower than Randy's so:
540 / 3t = (135 / t) + 15
540 = 405 + 45t
135 = 45t
time = 3 hours (Andy's Time)
Therefore Randy's Time = 9 hours
Randy's Rate = 540 / 9 = 60 mph
Andy's Rate = 135 / 3 = 45 mph