Question

The prime factorisation of $100$ is

Find the missing number.

• A. 25
• B. 50
• C. 100

Answer 1

The correct option is B 50

By Ladder Method:

Divide 100 by 2: Quotient = 50 with zero remainder,
Divide 50 by 2: Quotient = 25 with zero remainder,
Divide 25 by 5: Quotient = 5 with zero remainder
Then, prime factorization of $100=2\times 2\times 5\times 5$
Hence, the missing number is 50.