Answer:
$20 <= X < = $21
Explanation:
You are told that he loses by going over $21 or by buying all items and being less than $20.
That means the total amount of the items bought must be equal to 20 dollars or 21 dollars or be within the two amount of money.
If Mikel buys six bottles of shampoo, x represents the total amount for the six bottles of shampoo. Then, the compound inequalities for this expression will be x less than or equal to 21 dollars and x greater than or equal to 20 dollars. That is,
$20 <= X < = $21