Austin is baking apple pies and apple cakes. each pie takes three times the number of apples as each cake. he plans to make 2 pies and 4 cakes. he wrote down the expression 2(3x) + 4(x) to model his baking plans. what does the 3x represent? a. 3x represents the number of apples used in each pie. b. 3x represents the number of apples used in each cake. c. 3x represents the number of cakes and pies being made. d. 3x represents the total number of apples being used.