24-7 / 24 hours and 7 days

[Grace]

Test No. incompl/inter-60 "Cliches", question 1

She's got the kind of job that seems to keep her occupied all the time - 24-..........

(a) 4
(b) 5
(c) 6
(d) 7

Test No. incompl/inter-60 "Cliches", answer 1

She's got the kind of job that seems to keep her occupied all the time - 24-7.

Correct answer: (d) 7
_________________________

I dont get it!
why the answer is 7??
What does this sentence means?

[Alan]

This is a popular expression which means constantly/all the time. It is often used for a service that never stops, never closes. It comes from the idea of 24 hours a day and 7 days a week.
_________________
English as a Second Language
You can read my ESL story Word Story: Weather

[Hiwa]