A salesperson at a jewelry store earns 7% commission each week. Last week jarrod

number of student tickets sold (x) = 40

number of adult tickets sold (y) = 60

Step-by-step explanation:

Let x = number of student tickets sold

Let y = number of adult tickets sold

Given:

⇒ x + y = 100

Given:

⇒ 4x + 8y = 640

Rewrite  x + y = 100  to make x the subject:

⇒ x = 100 - y

Substitute  x = 100 - y  into  4x + 8y = 640  and solve for y:

⇒ 4(100 - y) + 8y = 640

⇒ 400 - 4y + 8y = 640

⇒ 4y = 240

⇒ y = 60

Substitute found value for y into x = 100 - y and solve for x:

⇒ x = 100 - 60

⇒ x = 40

To solve graphically, rewrite both equations to make y the subject:

y = 100 - x

y = 80 - (1/2)x

Plot both lines.

The solution is the point of intersection (40, 60)