math equation

Question

A local aquarium found that if the price of admission was $18, the attendance was about 1450 customers per day. When the price of admission was dropped to $11, attendance increased to about 1800 per day. Write a linear equation for the attendance in terms of the price, p. ( A=mp+b )

Answer 1

The two "data points" given should be consider as (x,y) coordinate pair.

 

Use the point-slope equation for a line:  y - y₁ = m(x - x₁)

 

Find the slope:

 

m = (change in y)/(change in x) = (1800-1450)/(11-18) = -50

 

Plug into point-slope equation for a line:

 

y - 1800 = (-50)(x - 11)

y = -50x + 550 + 1800

 

y = -50x + 2350

 

(Either point could have been used to plug into the point-slope equation, once you have found the slope.)