How do I solve this equation step by step?

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Iknow its nothing to do with education, but what type of thing should i wrote here? ? : ) its for mcdonald's btw.

As a salesperson you get $50/day and $3.60/each sales you make.if you want to make $60 in one day, how many sales would you need need to make ? a 3b 4c 5d 6 show work.