The statement which is true in the choices is the third item in the choices such as "Nina makes 20x dollars at the clothing store each week". It was clearly stated in the given that x represent the total number of hours she worked in a week. This statement made the other items in the choices wrong.
Because the distance a car travels is directlyrelated to the time it travels, the distance varies directly with the time: d=a*t. "a" would be the constant of variation. Just substituted the given values(300 and 5) into the equation, and you would get 300=5a. Divide both sides by 5 and you get a=60. So, the constant of variation is 60
