Answer:
The correct option is C.
Explanation:
It is given that Joshua sells a pack of pens for $3.15, which is 5 percent more than he pays for them.
Selling price of a pack of pens = $3.15
Let x be the amount he pays for a pack of pens.
x + 5% of x = 3.15
It can be written as



Divide both sides by 1.05.


The required equation is x+0.05x=3.15 and this equation has one solution.
Therefore, the correct option is C.