Randy drove 540 miles in three times the time it took andy to travel 135 miles andy’s speed was slower than randy’s by 15 miles per hour what were the rate and time of each? really need an answer for this question

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

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