Thank you for asking this question. Here is your answer:
We will consider the price of the truck to be $x
And the amount of tax in the percentage would be 13%
13/100
= $ 0.13x (this is the actual amount of the tax)
Now we will calculate the total price of the truck =
$x + $ 0.13x
= $ x(1 + 0.13)
If there is any confusion please leave a comment below.