Question

HOW DO I DO THIS QUESTION

The GCD and LCM of three numbers are 3 and 1008 respectively.If two of the numbers are 48 and 72.Find the least possible value of the third number​

Answer 1

21

Explanation:

We decompose prime factors of 48, 72, and 1008

48=2*2*2*2*3

72=2*2*2*3*3

1008=2*2*2*2*3*3*7

Let's compare 48, 72 with GOD(3) and LCM(1008), we can find that there must be at least 2 prime factors in the third number that is 3 and 7.

And let's find out the LCM of 48 and 72. Quite obvious the answer is 144.

Since the LCM should be the consequence of 144 multiplied by another prime factor.

Then let's try 144*7. Amazingly 144*7=1008. DONE!