Answer:
15
Step-by-step explanation:
Let us first write an equation where the unknown number is represented with variable x. The sum of a fifth of x and two is five:
[tex]\frac{1}{5} x+2=5[/tex]
Great! Let's solve for x by isolating the variable.
[tex]\frac{1}{5}x=3\\x=15[/tex]
Therefore, the unknown number is 15.
I hope this helps! Let me know if you have any questions :)