Ta linen sale mrs. earle bought twice as many pillowcases for $2 each as sheets for $5 each. if she spent less than $40, not including tax, what is the maximum number of pillowcases she could have purchased?

For this case, the first thing we must do is define variables:
 x: number of pillowcases
 y: number of sheets
 We now write the system of equations:
 2x + 5y = 40
 x = 2y
 Solving the system we have:
 x = 8.9
 y = 4.4
 
 The maximum number of pillowcases she could have purchased is:
 x = 8 (spent less than $ 40)