The total number of students is 158 + 139 = 297. This number can be rewritten as ...
297 = 37 × 8 + 1
That is, if there were 37 chaperones, 1 student would remain without a chaperone. That means the number of chaperones must be increased by 1 to 38. This is best explained by choice D.
The form ax2 + bx + c = 0 is called standard form of a quadratic equation. Before solving a quadratic equation using the Quadratic Formula, it's vital that you be sure the equation is in this form.
