Make 2 equations to find speeds of Kim and Julies

[MaginationX]

Kim and Julies are joining Nicole at her parents' cottage for the weekend. The cottage is 150km away from their neighborhood. Kim can leave directly after school but Julie will be leaving after band practice, an hour 15 minutes later. Kim took her time and drove slowly averaging 20km/h slower than Julie. They both arrived at the same time. At what speed were they traveling?

could any1 help me in finding the 2 equations or how to go about doing this?

 

[galactus]

Use the d=rt formula.

d/r=t

Kim: \(\displaystyle \L\\\frac{150}{\underbrace{r-20}_{\text{drove 20 km/h slower}}}=t\)

Julie: \(\displaystyle \L\\\frac{150}{r}=\underbrace{t-\frac{5}{4}}_{\text{left 1 hr and 15 min later}}\)

 

[MaginationX]

t = time
d = distance
r = v?(speed)

could u possibly explain a little more?

 

[jonboy]

r = rate , in this case speed.

 

[MaginationX]

oh ok i think i get it thank you for your help ^.^ both of you