What happened to 1 dollar?

Question

3 hungry kids went to a restaurant and eat.total bills end up to be 30 dollars and 50 cents.but they have only 10 dollar each. so they ask the manager if it will be okay because they are short of 50 cents. the manager said its okay so they left. On their way out the manager called one his staffs and handed 5 dollar bills to give it to the boys,but the staff thought it si better for him to give only three dollars so each one receive 1 dollar each. so he kept the 2 dollar for himself. here is the puzzle with a dollar back, each only contribute 9 dollar each so 9 times 3 = 27 + 2 dollar the staff keep for himself where is the one dollar?

Answer 1

he gave it to the staff

Answer 2

It is with the cashier!

Answer 3

idk...

Answer 4

i don't know