Question

You started on a bike trip, riding at a rate of 9 miles per hour. Your friend left
one hour later and rode at the rate of 12 miles per hour. How long did it take
your friend to catch up with you?

Answer 1

You're 9 miles ahead when the 2nd bike starts.
His speed wrt you is 3 mph (12-9).
9/3 = 3 hours

Answer 2

So it takes 3hours

Answer 3

Medal please.

Answer 4

I don't understand this.. I saw that same explanation on algebra.com and it doesn't make sense to me.

Answer 5

okay so your friend named oscar the grouch starts of an hour later, right?

Answer 6

by that time you sarah has covered 9 miles

Answer 7

but oscar is 3 miles faster ...

Answer 8

I also have to find the error in someone else's work for this problem. Her work is:

distance=rate x time.
your distance= your friends distance.
let t= your time(in hours)
let t+1=your friends time (in hours).
9t=12(t+1)
9t=12t+12
-3t=12
t=-4
A negative time does not make sense in this context, so the problem has no solution.

Answer 9

So to take the lead he needs to cover 9 miles

Answer 10

so 9/3 =3 voila

Answer 11

get it?

Answer 12

yes?no?maybe?i dont know?can you repeat?

Answer 13

I get it but I don't understand how to do the work.

Answer 14

okay, so use the equation 9+9x=12x

Answer 15

@sarahruth ?

Answer 16

so would it be 1.5?

Answer 17

how did you get 1.5?

Answer 18

9+9x=12x
9=3x
3=x