Answer :

Sure, let's solve the problem step-by-step.

1. Define the unknown number:
Let [tex]\( x \)[/tex] be the unknown number we need to find.

2. Set up the equation:
According to the problem, five added to one third of this number is equal to twice the number. Mathematically, this can be written as:
[tex]\[ 5 + \frac{1}{3}x = 2x \][/tex]

3. Eliminate the fraction:
To remove the fraction, we can multiply every term in the equation by 3:
[tex]\[ 3 \cdot 5 + 3 \cdot \frac{1}{3}x = 3 \cdot 2x \][/tex]

4. Simplify the equation:
When we simplify, it becomes:
[tex]\[ 15 + x = 6x \][/tex]

5. Rearrange to isolate the variable [tex]\( x \)[/tex]:
We need to get all the terms involving [tex]\( x \)[/tex] on one side of the equation. So, we subtract [tex]\( x \)[/tex] from both sides:
[tex]\[ 15 = 6x - x \][/tex]
Simplify the right side:
[tex]\[ 15 = 5x \][/tex]

6. Solve for [tex]\( x \)[/tex]:
To isolate [tex]\( x \)[/tex], divide both sides of the equation by 5:
[tex]\[ x = \frac{15}{5} \][/tex]
Simplify:
[tex]\[ x = 3 \][/tex]

So, the unknown number is [tex]\( \boxed{3} \)[/tex].