Question

The HCF of $455,42$using Euclid algorithm is

• A. $7$
• B. $6$
• C. $5$
• D. $4$

Answer 1

The correct option is A

$7$

Euclid’s division lemma states that,

Any positive real number a can be represented as$a=bq+r$where $b$ is greater than $0$ and is called the divisor of$a$ and $r$ is remainder obtained after dividing$a$ by $b$

Given numbers are $455,42$

So,

$455$ can be written as,

$455=42x10+35$

Using Euclid’s division algorithm on$42,35$, we get,

$42=35x1+7$

Again using Euclid’s division algorithm on $35,7$, we get,

$35=7x5+0$

We get a $0$ remainder. So we will stop using Euclid’s division algorithm

Since,$7$ is the last non-zero remainder

Hence, the HCF of $455,42$is $7$