Question

(i) Find the LCM and HCF of 10, 15 and 20.
(ii) Find the sum of the prime factors of 1729.

Answer 1

(i)
10 = 2$\times$ 5
15 = 3 $\times$ 5
20 = 2 $\times$ 2 $\times$ 5
LCM = 2 $\times$ 2 $\times$ 3 $\times$ 5 = 60
HCF = 5

(ii) The prime factors of 1729 = 7 $\times$ 13 $\times$ 19
Therefore, the sum of prime number = 7 + 13 + 19 = 39.