If LCM and HCF of two numbers are 4 and 48 respectively and one of the numbers is 12 then what is the second number?

Given: 

LCM and HCF of two numbers are 4 and 48 respectively.

One of the numbers is 12.

To do: 

We have to find the second number.

Solution:

Let the required number be $a$.

We know that,

LCM $\times$ HCF $=$ Product of the two integers

Now, 

$4\times48 = 12\times a$

$192=12a$

$a=\frac{192}{12}$

$a=16$

The second number is $16$.