Question

Choose the pair of co-prime number.a)6,20 b)11,44 c)11,15 d)9,21

Answer 1

Answer:

c) 11 and 15

Step-by-step explanation:

11 and 15 have no common factor except 1

Answer 2

The pair of co-prime numbers is - c)11,15.

Given:

The pair of co-prime numbers a)6,20 b)11,44 c)11,15 d)9,21.

To Find:

We have to find the pair of co-prime numbers.

Solution:

This is a simple problem of prime numbers.

Let us tackle this problem.

We can easily solve this problem as follows,

1st we check option a,

We know,

6 = 2×3

20 = 2× 2×5

So, 6 and 20 have a common divisor 2 (other than 1).

Thus, they are not co-prime numbers.

Now, we check option b.

We know,

11= 11×1

44 = 11×4

Thus, 11 and 44 are co-prime numbers as they have a common divisor 11 (other than 1).

Then we check option c.

11= 11×1

15=15×1

We see that 11 and 15 have no common divisor other than 1.

So, they are co-prime.

Now, we check option d.

9= 3×3

21=3×7

So, they are not co-prime numbers as they have a common divisor 3( other than 1).

Hence, the pair of co-prime numbers is c)11,15.

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