Answer:
21 days
Explanation:
if you do 1/7 of the task in 3 days, you must do 7/7 of the task to finish
to make 1/7 7/7 you must multiply it by 7
so you set the equation up like this
3 * 7
and you get 21 as how long she works
4.5m questions
5.9m answers