the ratio of numbers is 4 : 5 and their h . c . f is 4 . their l . c . m is :
"let the numbers be 4 x and 5 x . then their h . c . f = x . so , x = 4 . so , the numbers are 16 and 20 . l . c . m of 16 and 20 = 80 . answer : a"
lcm(multiply(4, 4), multiply(5, 4))