Question

to sell an item in an online auction webauctions charges a $5 listing fee plus 10% of the final selling price. AuctionsOnline charges a $3 listing fee plus 15% of the final selling price. For what final selling price do both companies charge the same amount? What will that amount be?

Answer 1

Many problems involving quantities and relationships between them can be described through algebraic equations, for this it is necessary to look at the described problem and the mathematical relationship involved (sum, equality, multiplication, etc.).

For this case we must postulate the two equations described, Webauctions $W$ and the costs of AuctionsOnline $W$, and match them based on the final sale price $x$, and then clear it:

$W = 5 + 0.1x\\A = 3 + 0.15x\\W = A\\5 + 0.1x = 3 + 0.15x\\2 = 0.05x\\\bf x = \ 40$

To determine the quantity, the value must be replaced in one of the equations

$5 + 0.1 (40) = \ 9\\3+0,15(40)= \ 9$

Answer

The final sale price at which both companies charge the same amount is $40.

The amount is $9.