Answer:
a)$102
b)$76.50 more
Step-by-step explanation:
Well, for the first part, you can see she bought one fan at 55% off and one at 70% off. You can average this to 62.5% off for each fan [(55+70)/2], so then you multiply the price she paid ($127.50) by the reciprocal of the percent she got off of the fans. $127.50 * 100/62.5 = 204, which you divide by 2 because she got 2 fans to get the original price of $102 a fan
For the second part, you know that Nick bought 2 fans for $204 because that's the original price for 2 fans. Then you subtract the price Xinyi paid to get $76.50 more
