You need four new pillows. you decide to buy neither the least expensive nor the most expensive. how much will your pillows cost? medium pillow: $18.49, large pillow: $22.69 and small pillow: $15.99 (re-worded)

Since we neither want most expensive nor least expensive, we need to go with pillow which is costing $18.49.

So total 4 pillows cost = 4*18.49
= $73.96

Considering there are only 3 options, we can deduce that the medium pillow is the pillow you decided to buy. Multiply the price of the medium pillow ($18.49) by 4 to get the final result. 
18.49
x     4

 73.96

Your total cost is $73.96

No because if you do the higher number minus the lower number you will get a positive. if you do it the other way around you will get a negative number