The cost for children under twelve at a certain buffet restaurant is a base charge of a dollar plus twenty-five cents for each year of the child's age. represent this cost as an expression, using y to stand for the child's age in years. then use the expression to find the cost for a child who is nine. 1 + 0.25y; $2.25 0.25 + y; $8.75 0.25 + y; $9.25 1 + 0.25y; $3.25