Please help it’s for a test!

The vet charges $45 for an office visit and $10 for each vaccination your dog needs. write an eaquation

You and a friend went to the movies. you spent half your money on tickets. then you spent 1/4 of the money on popcorn, $2 on candy, and $3 on a soda. if you have $1 left, hiw much money did u take to the movies?

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.