Question

2. List all the prime factors of the following
numbers and find their HCF.
a. 20, 28 b. 12.40 c. 30,75
d. 72,100 e. 63, 108 £. 80, 120
g. 12, 20 h. 24, 60 i. 32, 56
j. 40,60 k. 54,12 L 65,91​

Answer 1

Step-by-step explanation:

a. 20: 2*2*5

28: 2*2*7

HCF: 2*2=4

b. 12: 2*2*3

40: 2*2*2*5

HCF: 2*2=4

c. 30: 2*3*5

75: 3*5*5

HCF: 5

d. 72: 2*2*2*3*3

100: 2*2*5*5

HCF: 2*2=4

e. 63: 3*3*7

108: 2*2*3*3*3

HCF: 3*3=9

f. 80: 2*2*2*2*5

120: 2*2*2*3*5

HCF: 2*2*2*5=40

g. 12: 2*2*3

20: 2*2*5

HCF: 2*2=4

h. 24: 2*2*2*3

60: 2*2*3*5

HCF: 2*2*3=12

i. 32: 2*2*2*2*2

56: 2*2*2*7

HCF: 2*2*2=12

j. 40: 2*2*2*5

60: 2*2*3*5

HCF: 2*2*5=20

k. 54: 2*3*3*3

12: 2*2*3

HCF: 2*3=6

l. 65: 5*13

91: 7*13

HCF: 13