Answer:
5 square 10 yards
$40
Explanation:
Mario:
20 + 4x
Her competitor:
10 + 6x
Where,
x = number of 10 square yards
Equate the expressions
20 + 4x = 10 + 6x
Collect like terms
20 - 10 = 6x - 4x
10 =2x
Divide both sides by 2
x = 10 / 2
= 5
x = 5 square 10 yards.
Charge at that moment
Using any of the cost equation
10 + 6x
= 10 + 6(5)
= 10 + 30
= 40
$40
Or
20 + 4x
= 20 + 4(5)
= 20 + 20
= $40