Is 15 and 1/4 a mixed number or an improper fraction? improper fraction mixed number

For how answer my question this will be the last question can you answer in math subject

What is the first step of an indirect proof of a number that is divisible by two

Samantha is growing a garden in her back yard. she spend $90 setting up the garden bed and buying the proper garden supplies. in addition, each seed she plants cost $0.25. a. write the function f(x) that represents samantha's total cost on her garden. b. explain what x represents. c. explain what f(x) represents. d. if samantha plants 55 seeds, how much did she spend in total?