Can anyone answer this?

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers

9/10 divide by -3/15 as a mixed number

Check all that apply. f is a function. f is a one-to-one function. c is a function. c is a one-to-one function.