Eureka Smartphones


The Situation

Luke wants to buy a cell phone plan that does not cost him much. He comes across two plans in The Eureka Smartphone. The first cell phone plan cost $48 monthly for unlimited minutes of usage. The second cell phone plan costs $10 monthly and $0.05 per minute. Now the question is which plan to buy? To make the decsion, Luke decides to make a scattor plot on the number of minutes and its cost for both Plans.

Recored data for both plans

Big image

Identifying the Variables

Independent Variable : cost
Depented Variable : number of minutes used


Plan 1


The slope is equal to 0

hence the line will be horizontal, with the y- intercept of 45

Plan 2


Slope= Δy / Δx

= 20-15/20-10

= 5/10

= 0.5

y= 0.5x + b

since line passes through (10,15). substitute x= 10 and y= 15


15 = 5 +b




Point of interaction

$45= 0.5x + $10
$45 - $10= 0.5x
$35= 0.5x
$35/0.5= x
70 = x

Point of interaction (70 minutes, $45)
Big image


In conclusion, Luke chooses plan 2 until he reaches 70 minutes, than he will switch to plan 1 because will be cheaper than plan 2.