Answer:
$336
Explanation:
When Lilian works 7 hours a day for 5 days in a week, she earns $420.
When she works 7 hours a day for 4 days a week , her weekly earnings are reduced by 20%.
This means that her new earning is 80% of her prior earning.
Lilian's new earning =
=
=
Hence the new weekly earning of Lilian is $336.