Distance,speed, time

[Francis]

Stuck on this...

Carrie walks at 3mph
Crystal rides bicycle at 9 mph

Traveled the same distance to school.

Carrie takes 20 minutes longer to get to school.

What is the distance to school.

d = r x t

carrie: d= 3mph (t + 20)
Crystal: d= 9 mph (t)

 

[Mrspi]

Stuck on this...

Carrie walks at 3mph
Crystal rides bicycle at 9 mph

Traveled the same distance to school.

Carrie takes 20 minutes longer to get to school.

What is the distance to school.

d = r x t

carrie: d= 3mph (t + 20)
Crystal: d= 9 mph (t)

You haven't said what t represents!

I ASSUME you mean this:

t = hours it takes Crystal to get to school

Note that the time is in HOURS. So, if it takes Carrie 20 minutes longer than Crystal, Carrie's time is t + (20/60) hours, or t + (1/3) hours.

distance for carrie = 3[t + (1/3)]
distance for Crystal = 9t

They both go the same distance...

Carrie's distance = Crystal's distance
3[t + (1/3)] = 9t

Solve that for t, and you will have the number of hours it takes Crystal to get to school. And when you know Crystal's time, you can find Crystal's distance: 9*t