Question

Use prime factorization to find the LCM of each set of numbers:A) 15,21B)15,30C)24,72D)16,42E)8, 30F)18,30G) 8,16,20

Answer 1

Solution

For this case we can do the following:

A) 15, 21

LCM= 105

15= 3*5

21 = 7*3

LCM= 3*5*7

b) 15,30

LCM= 30

15= 3*5

30 = 2*5

LCM= 2*3*5= 30

c) 24,72

LCM= 72

24= 2*3*4

72= 2* 2*2*3*3

LCM= 2*2*2*3*3

d) 16,42

LCM= 336

16= 2*2*4

42= 2*3*7

LCM= 2*2*3*7*4

e) 8,30

LCM=120

8= 2*4

30= 2*3*5

LCM= 2*3*4*5=120

f) 18,30

LCM=90

18= 2*3*3

90= 2*5*3*3

LCM= 2*5*3*3

g) 8,16,20

LCM= 80

8= 2*2*2

16= 2*2*2*2

20= 2*2*5

LCM= 2*2*2*2*5