For every 4 hotdogs there is 1 hamburger being sold.
We can use quadratic formula to determine the roots of the given quadratic equation.
The quadratic formula is:

b = coefficient of x term = 4
a = coefficient of squared term = 1
c = constant term = 7
Using the values, we get:
So, the correct answer to this question is option A
<em>Answer:</em>
<em>n = 12</em>
<em>Step-by-step explanation:</em>
<em>85%×n = 10.2</em>
<em>85n/100 = 10.2</em>
<em>85n = 1020</em>
<em>n = 1020 : 85</em>
<em>n = 12</em>