Problem:
My friend sets out walking at a speed of 3 miles per hour. I set out behind her 5 minutes later at 4 miles per hour.

For how many minutes will my friend have been walking when I catch up to her?

Question

Problem:
My friend sets out walking at a speed of 3 miles per hour. I set out behind her 5 minutes later at 4 miles per hour.

For how many minutes will my friend have been walking when I catch up to her?

anonymous · Answer

pls answer

danjs · Answer

distance = rate * time

i would use a universal time for both,  and call hers T and yours  T-5
since you add no distance for the first 5 min

when you catch up to her, both distances are the same, and equate them


3 * T   =  4 * (T - 5)


she moves at 3mph for T time, and you move at 4mph for T-5 time

solve for Time T when you catch up

danjs · Answer

i just realized T is in minutes and the rate is in hour,  
since they want minutes , change the rates to miles per minute

(3/60) * T = (4/60) * (T - 5)