lt;bAdvance purchase discounts for airline

Question

Advance purchase discounts for airline travel
Days prior to departure ----- % discount
0-6 days-------0%
7-13 days ----10%
14-29 days ---25%
30 days or more--40%

The table above shows the discount structure for advanced purchase of tickets at a particular airline. A passenger bought a ticket at this airline for $1050. The ticket agent told her that if she had bought it one day later, she would have paid paid $210 more. How many days before her departure did she purchase her ticket?

Choices: 6, 7, 13, 14, or 29 days?

Can somene explain to me why the answer is 14 days?

tarek99 · Answer

Here is how you do it. First of all, I will organize your table from 1 to 4, showing the remaining percentage after each of those discounts: 

1) 100% 
2) 90% 
3) 75% 
4) 60% 

The ticket agent then said that if that person bought the ticket 1 day later, the amount would have increased. Therefore, we must be talking about either day 7, 14, or 30, otherwise, there is no reason for the amount to increase 1 day later in any other days, right? and the best part is that the answer choices have given us only 7 and 14, so we can eliminate other answer choices. So we should examine both 7 and 14: 

The initial amount was $1050. When you add $210 to the initial amount, you will have a total of $1260. So work with the percentages to see which one will give us the total of $ 1260. I'll start with day 14 to 13: 

.75/.9=1050/X 
This means that if 1050 happens to be 75%, then what will 90% be? 

X= 1260 so that percentage increase matches with our total answer. 

for the sake of practice, i'll also work the on increase from day from 7 to 6: 

.9/1 = 1050/X 
This means that if 1050 is 90% of the amount, then what will 100% be? 

X= 1166.6 
this increase does not match with our increased amount of 1260. Therefore this is not the correct day, but rather day 14 is our correct answer. 

Does that make sense? hope it does. 
take care

tino · Answer

Where does this question come from? Thanks.

aliensoybean · Answer

Hey tarek, sorry for the late response, been swamped the last few days with work. 

Anyway, I read through your explanation and I see how you did it. But I got stuck at your 0.75/0.95 = 1050/X rationale. I understand that it means "going from 75% to 90% of the price equates to going from 1050 to what dollar." But I am stuck because....how did you know to do this.

I always run into this type of problem, where i dont know what to do with the % given....

This problem is from the 2006 Princeton Review book.

tino · Answer

Thanks. If you don't mind, I'd like to move this question to the Math Q forum. Let's try to keep this forum for GMAT Club test - related questions only.

tarek99 · Answer

aliensoybean, I knew how to do this because I knew that I was dealing with a ratio problem. are you familiar at all with ratios? and by the way, don't even touch princeton books, especially when you don't have your foundations set in stone. consider gmaxonline.com. if you want to improve in both your math and english skills from scratch to advanced level, then you better go for their online courses. 

I used princeton and it never helped me at all. one should consider learning the tricks and shortcuts ONLY after when you have learnt all the material properly. but even when you have learnt the material, the tricks and shortcuts from princeton will no longer matter for you anymore.

aliensoybean · Answer

Yea, I need to work on ratios and %. I am okay with the basics, but sometimes I forget. I'll check out the website you recommended. thanks so much! 

Tino, yes, sorry, no problem

lt;b>Advance purchase discounts for airline

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