Question

A boy was asked to find the L.C.M OF 3,5,12 and another number.But while calculating he wrote 21 instead of 12 and yet came with the correct answer.What could be the fourth number

Answer 1

hey buddy here is your answer

hope it helps you

Step-by-step explanation:

Solution:-

Let the fourth number be 'a'

Suppose LCM of 3, 5, 12 and a = x

And LCM of 3, 5, 21, and a = y

Using prime factorization,

12 = 2 × 2 × 3

21 = 3 × 7

Given : x = y

So, a should contain the factors 2 × 2 ×7

Thus, a = 2 × 2 × 7 = 28

Again using prime factorization,

3 = 3

5 = 5

12 = 2 × 2 × 3

21 = 3 × 7

28 = 2 × 2 × 7

So, L. C. M. of 3, 5, 12, and 28 = 3 × 5 × 2 × 2 × 7 = 420

L. C. M. of 3, 5, 21 and  28 = 3 × 5 × 2 × 2 × 7 = 420

So, the fourth number is 28

Answer.

please mark me at brainliest

Answer 2

Answer:

I think in your question there shouldn't be 5