How I Stopped An Alien Invasion Using Proportion

One day I was walking around school, and I saw people crowding up the hallways in a circle. So I ran and shoved people out of the way. As I got to the front, I noticed a strange vehicle parked right there, and a whole in the ceiling. I was confused with what was going on until I saw these strange purple monsters. Turns out they were aliens. They then walked up to me and made me answer 3 proportion questions or else they wouldn't leave. So I guess I had no choice but to do it.

The first problem they asked me was-

Delia was paid $35 for 5 h of babysitting. How much should she receive for 3 h? Use a unit rate to find the answer.
I replied " Delia should receive $21 for 3 h of babysitting " They made me show my work so here it was.

The second problem they asked me was-

David can saw a log into three pieces in 7 minutes. If he continues sawing at a constant rate, how long will it take him to saw a similar log into 6 pieces?
My answer was " It would take him 14 mn to saw 6 pieces. " So here is my work again

The third problem they asked me was-

Last night 30 cm of snow fell in 6 hours. If it continues snowing at the same rate, how long will it takefor 45 cm of snow to fall ?
The final answer was " It would take 9 hours for 45 cm of snow to fall " Heres what I did.