a ratio between two numbers is 7 : 9 and their l . c . m . is 189 . the second number is
"sol . let the required numbers be 7 x and 9 x . then , their l . c . m . is 63 x . ∴ 63 x = 189 ⇔ x = 3 . hence , the second number is 27 . answer d"
multiply(divide(189, multiply(7, 9)), 7)