Using Cavalieri’s Principle, what is the general formula for the volume of a square pyramid?

Max and brenda went shopping for a table. they found one that they like. the cost is $150.00 but there is a 25% off sale and they need to add 8% to the local sales tax. max multiplied 150 x 0.75 to get the cost. he then multiplied the discounted amount by 1.08 to find the total cost. what was max’s total cost? brenda multiplied 150 x 25% and subtracted that amount from 150. she then multiplied the discounted price by 8%. she added the discounted price and the tax amount together to get the total cost. what was brenda’s total cost? how come the answers are the same?