Which of the following pairs of functions are inverses of eachother?

Sara bought a pair of pants that were on sale for 30 percent off of the original price. if the original price of the pants was $29, what was the sales price of the pants?

Acar traveling at 65 mph leaves 25 foot skid mark what is the ratio of the speed to length of skid mark (feet) in the simplest form

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?