Find the common factors and HCF of each of the following pairs.
a) 13 and 39
b) 32 and 64 c) 45 and 90 d) 10 and 80
Answers
Answer:
(i) 18, 48 (ii) 30, 42 (iii) 18, 60 (iv) 27, 63
(v) 36, 84 (vi) 34, 102 (vii) 70, 105, 175
(viii) 91, 112, 49 (ix) 18, 54, 81 (x) 12, 45, 75
SOLUTION:
i) 18,48
18=2\times3\times318=2×3×3
48=2\times2\times2\times2\times348=2×2×2×2×3
The common factor of 18 and 48 are 2,3. thus, HCF of 18 and 48 is2\times3=62×3=6
ii) 30,42
30=2\times3\times530=2×3×5
42=2\times3\times742=2×3×7
The common factor of 30 and 42 are 2 and 3
thus, HCF of 30,42 are 2\times3=62×3=6
iii) 18,60
18=2\times3\times318=2×3×3
60=2\times2\times3\times560=2×2×3×5
The common factor of 18 and 60 are 2,3. thus, HCF of 18 and 60 are 2\times3=62×3=6
iv) 27, 63
27=3\times3\times327=3×3×363=3\times3\times763=3×3×7
The common factor for 27 and 63 is 3
thus, HCF of 27 and 63 is 3\times3=93×3=9
v) 36,84
36=2\times2\times3\times336=2×2×3×384=2\times2\times3\times784=2×2×3×7
The common factor of 36 and 84 is 2\times32×3
thus, HCF of 36 and 84 is 2\times2\times3=122×2×3=12
Answer:
because 13 comes in table of 1,3,13 and 39 comes in table of 1,3,13,39 so common factor is 1,3,13 and H C F is 13