Help please? 15 points here

2-digit numbers less than 91 which are 1 less than a multiple of 10

The difference of 2 numbers is 21 and the quotient of the equation is 4 then what are the two numbers?

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