Question

The least number divisible by each of the numbers 15, 20, 24, 32 and 36 is
(a) 1660
(b) 2880
(c) 1440
(d) none of these

Answer 1

(c) 1440
The least number divisible by each of the numbers 15, 20, 24, 32 and 36 is their L.C.M.
$\begin{array}{l}2\overline{)15,20,24,32,36}\\ 2\overline{)15,10,12,16,18}\\ 2\overline{)\text{15, 5, 6 , 8, 9}}\\ 2\overline{)\text{15, 5, 3, 4, 9}}\\ 2\overline{)\text{15, 5, 3, 2, 9}}\\ 3\overline{)\text{15, 5, 3, 1, 9}}\\ 3\overline{)\text{5, 5, 1, 1, 3}}\\ \text{5}\overline{)\text{5, 5, 1, 1, 1}}\\ \text{1, 1, 1, 1, 1}\end{array}$
L.C.M. = 2⁵ × 3² × 5
= 1440