Plz help I dont get it

Given a(-12,5) and b(12,29) find the point that divides the line segment ab three-eighths of the way from a to b

Twenty-five percent of the customers entering a grocery store between 5 p.m. and 7 p.m. use an express checkout. consider five randomly selected customers, and let x denote the number among the five who use the express checkout.

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.