The product of two numbers is
.
Let
and
be the two positive numbers.
Therefore,
.
The sum of first number and three times the second number is minimum,
\Consider above sum function as
.
Thus, 
is minimum.

Substitute
value in
.

.
Differentiate the function
.

Find the critical numbers by equating derivative to zero.
\
.
Substitute
value in the expression
.

.


is minimumu when
and
.
The two numbers are
and
.
The two numbers are
and
.