Question 9359: I was able to solve Marilyn Savant's Monty Hall question yet this one fooled me at first because intuitively I would add the percentages in the following question and then solve for the final value discount however the “correct answer” requests you to solve using a different method (solve for the first discount and proceed to solve for the next discount)
I just want to know why you would solve this way .8 x .85 x 450 = $306 and not this way .65 x 450 = $292.50…
"Employees of a discount appliance store receive an additional 20% off of the lowest price on an item. If an employee purchases a dishwasher during a 15% off sale, how much will he pay if the dishwasher originally cost $450?"
Answer by longjonsilver(2297)   (Show Source):
You can put this solution on YOUR website! it is all to do with how a question is worded to be honest. You have to follow the English of it and then act accordingly
So lets look at 2 "versions" of a question:
A. A $100 item is given a 20% discount. From this, a further 15% is taken off. What is the final sale price?
B. A $100 item is given a 35% discount. What is the sale price?
OK, A has 0.80*100 --> $80 and then 0.85*80 --> $68
or all together, 0.85*(0.80*100) --> 0.68*100
Now B has just 0.65*100 --> $65
In essence, in A, we have 20% taken from the original price and THEN 15% taken off another "intermediate" price to arrive at $68. Whereas, in B, the full 35% is taken off the original price.
Hope this clarifies it? :-) But, yes, you are correct... it is confusing and you have to be careful AND the question setter has to be very careful with their wording too, to avoid any misunderstandings like this.
jon.
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