martin buys a pencil and a notebook for 80 cents . at the same store , gloria buys a notebook and an eraser for 85 cents , and zachary buys a pencil and an eraser for 45 cents . how many cents would it cost to buy 3 pencils , 3 notebooks , and 3 erasers ? ( assume that there is no volume discount . )
pencil + notebook = 80 notebook + eraser = 85 pencil + eraser = 45 let ' s add all three equations . 2 pencils + 2 notebooks + 2 erasers = 210 cents the cost to buy 3 of each would be ( 3 / 2 ) ( 210 ) = 315 the answer is b .
add(add(multiply(subtract(45, subtract(80, divide(add(85, subtract(80, 45)), const_2))), 3), multiply(subtract(80, divide(add(85, subtract(80, 45)), const_2)), 3)), multiply(divide(add(85, subtract(80, 45)), const_2), 3))