Step-by-step explanation:
Multiply the cost of an item or service by the sales tax in order to find out the total cost. The equation looks like this: Item or service cost x sales tax (in decimal form) = total sales tax. Add the total sales tax to the Item or service cost to get your total cost.
Well, when it comes to math, I gotta admit, I'm not the smartest cookie in the cookie jar, but if you take 20 2/5 and divide it by 2/5, you should be left with the number of sheets of sheetrock there are in the stack. To divide it, you my have to convert the fraction to a decimal, just FYI. Considering this is marked as a college-level question, I assume you already know how to do this. Hope this helps ya, pal.
3.56 +/- 0.011 = ( 3.549, 3.571). This is the answer.