Answer this simple quick question!! Pls :)

Afamily of five rents a kayak and splits the total time, k, equally. each family member spent less than 25 minutes kayaking. which values can be used to complete the math sentence below so that it accurately represents the situation? intro done

Ingredient c: 1/4 cup for 2/3 serving or ingredient d: 1/3 cup for 3/4 serving which unit rate is smaller

3x = 729 solve for x plz . it's urgent. will mark