Question

The basic price to enter a mall is $\$$80 plus an additional charge for every hour. Suppose one pays $\$$230 for 3 h, the equation for above is .

• A. y = 80x + 50
• B. y = 80x + 60
• C. y = 50x + 80
• D. y = 50x + 60

Answer 1

The correct option is C y = 50x + 80

Let's assume y as the total charge and x as the number of hours spent at0 the mall.

Equation of line in slope intercept form, y = mx + c

It is given that basic price = $\$$80
$⟹$ y-intercept, c = 80

$⟹$ y = mx + 80 -------(1)

It is given that total amount paid (y) for 3 h is $\$$230.

Substitute the above values in equation (1), we get:
230 = 3m + 80
$⟹$ 230 - 80 = 3m
$⟹$ 150 = 3m
$⟹\frac{150}{3}$ = m
$⟹$ m = 50

$\therefore$ The equation is y = 50x + 80.