How many ways can you choose 3 out of 5 books if order doesn't matter

Since order doesn't matter, we can simply use the combination notation cited as:
, where n represents the number of objects and r represents the number of subsets.

If we were to choose 3 books from a pack of 5, we can choose them in ways, which is 10 ways.

There is no list of items and their correct and incorrect prices, thus actual and accurate answers cannot be determined.

Step-by-step explanation:

N.B: Since no list is given, accurate answers cannot be given.  

The typing of the bar codes or prices manually in order to determine the price, can lead to errors in the selling price. This can be detrimental for business since undercharging or overcharging can occur.

For example, the price of a dress was recorded as $30 while it should have been $39. The price of a t-shirt was correctly recorded as $10. The price of a pair of jeans was recorded as $25 instead of $23. There are 2 errors in the selling prices found in the above example about clothing items.   the dress is undercharged and the pair of jeans is overcharged.