Final answer:
The sentence that uses both hyphens and dashes correctly is: 'Checkouts 1 and 2—the ones at the front of the store—are for self-service customers only.'
Step-by-step explanation:
The sentence that uses both hyphens and dashes correctly is:
Checkouts 1 and 2—the ones at the front of the store—are for self-service customers only.
In this sentence, the hyphen is used to show a range of checkouts, and the dashes are used to add additional information about the location of those checkouts.
Learn more about Proper usage of hyphens and dashes