Help with 2 simple highschool physics Problem

[pamba]

I am really tired and i can't sem to thik right. Please help with these 2 questions

Homework Statement

1. If you must average 60 km/h for a 90-km trip, and only average 40 km/h for the first 40 km, wha velocity must you average the rest of the way?

2. Juanita left on a walk 45 min ago. She is traveling a 4.5km/h. How fast must you travel to catch up to her in 1.0 h?

Homework Equations

v: d/t

The Attempt at a Solution

??

 

[dlgoff]

1. How much time would it take if you were going 90km at 60km/h?
How much time have you spent going 40km/h?
So how fast will you have to go for the next 50km in the time you have left?

 

[matadorqk]

#2

As for #2, how much has Juanita traveled in 45 minutes?
How much will she have traveled once you have caught up to her? (in 1 hour and 45 mins)

that should help
qk