Method 2
PRIME FACTORIZATION METHOD
Find the LCM of the following set of numbers
using prime factorization method:
a. 15, 18
b. 2, 7, 9
c. 6, 12, 18, 36
Solutions
a). 15 = 3 x 5
18 = 2 x 32
The LCM is 2 x 32 x 5 = 2 x 9 x 5
= 2 x 45
= 90
b). 2 = 2 x 1 ;7 = 7 x 1 ;9 = 32
The LCM is 2 x 7 x 32= 126
c). 6 = 2 x 3
12 = 22 x3
18 = 2 x 32
36 = 22 x 32
The L.C.M is 22 x 32 x 5 = 4 x 9 = 36
Two bells ringing in such a way that the first bell
rings after every 2 hours and the second rings after
every 3 hours. If they ring together at a certain time,
after how long will they ring together again?