Multiple choice Three numbers are in the ratio 1 : 2 : 4 and their LCM is 280. Find their HCF. 15 30 45 40 Reveal answer Fill a bubble to check yourself D Correct answer Explanation The ratio of three numbers is 1:2:4 1x, 2x, 4x and LCM = 280 1 x + 2 x + 4x = 280 7x = 280 x = 40 HCF = 40