In your own words.
why is it important to the business to motivate

This is mainly opinionated, and since I'm young I may be wrong.

I say it's good to motivate them because then they will do a better job at their task and will make you seem like a good boss/person, especially if it's a decent pay that will keep them being able to live. With the motivation, they might even remember more things (Such as: If you work at a gas station, you remember to upsell people when a deal is going on, whereas unmotivated people forget or just don't want to do it and be lazy). It's the same effect of giving a kid a piece of candy for being good, doing chores, or getting a harder question right.

there's 11 people for the 1st position. then, no matter who gets it, there's only 10 left for the second, and then 9 left for the third. 11 x 10 x 9 = 990.   the answer is there are 990 different ways the positions can be filled by these applicants