Answer:
She is not correct.
Explanation:
If she originally purchases the teas for $100 and then she marks the price up 20%, the retail price would then be 100 + 0.20(100) = 100 + 20 = 120. The sales price would then be 120 - 0.2(120) = 120 - 24 = 96. This is less than the purchase price, so she is losing money, rather than gaining.
I hope this helps. If you download an app called Slader, it has the same math book you are using with the answers.