in an apartment building that has 490 units , 4 out of every 7 units are currently rented , including 1 / 3 of the one - bedroom units . if , of the rented apartments , there is a 6 : 1 ratio of two - bedroom units to one - bedroom units , and the building only consists of two - bedroom and one - bedroom units , how many two - bedroom units are not rented ?
"rented = 4 / 7 * 490 = 280 . rented two - bedroom = 6 / 7 * 280 = 240 ; rented one - bedroom = 1 / 7 * 280 = 40 ( or 280 - 240 = 40 ) . rented one - bedroom units are 1 / 3 of all one - bedroom : 1 / 3 * { all one bedroom } = 40 - - > { all one - bedroom } = 120 { all two - bedroom } = 490 - 120 = 370 . two - bedroom not rented = 370 - 240 = 130 answer : d ."
subtract(subtract(490, divide(subtract(multiply(4, divide(490, 7)), multiply(3, divide(multiply(4, divide(490, 7)), add(3, 1)))), divide(1, 3))), multiply(3, divide(multiply(4, divide(490, 7)), add(3, 1))))