Answer:
20%
Step-by-step explanation:
You want to know the tax rate if the added tax brings the cost of $45 purchase to a total of $54.
The multiplier applied to a purchase cost to add the tax is ...
(1 +r)
where r is the tax rate.
Here, that means ...
45(1 +r) = 54
1 +r = 54/45 = 1.20
r = 1.20 -1 = 0.20 = 20%
The tax rate Delia paid on the articles she bought was 20%.
