I need help with these problem

Sara needs to take a taxi to get to the movies the taxi charges $4.00 for the first mile and then $2.75 for each mile after that if the total charge is $20.50 then how far was sara’s taxi ride to the movie

Candy lives in the center of town. her friend darlene lives 28 miles to the east and her friend dana lives 21 miles north. approximately how far do dana and darline live apart ?

Out of $20$ creepy-crawly creatures in a room, $80\%$ are flies and $20\%$ are spiders. if $s\%$ of the total legs belong to spiders, what is $s$?