700-800 level problems pls.

[CyberSpy]

Can some one tell me from where I can get 700-800 level problems?

you can also post some very hard questions in this thread.

[cliq]

you can search for questions by kevinspain

[cliq]

sample brain teaser

Employees of a department store receive a 20% discount on the sale price of all store merchandise. As the holiday season is coming to an end, some of the socks in the menswear department have been marked down by 40%, and the rest have been marked down by only 10%. Sean, a department store employee, bought 16 pairs of socks whose original price were $10.00 each. Were most of the pairs marked down by 40%?

(1) He paid for the socks with a $100 bill.
(2) If Sean were not a department store employee, he would paid less than $120.

[kssshah]

Interesting question. The way information is laid out does not give the confidence that what you assume is correct.
So Solving the percentages, if the store employee was to take all the discounts, he would have bought the socks for $4.8 and $7.2 respectively. If he was not a store employee, the socks would have cost $6 and $9 respectively. Assume he bought 'a' quantity of 40% discount sock and 'b' quantity of 10% discount socks. a+b = 16
Statement 1 gives 4.8a + 7.2b < 100 ( i have to assume it means < 100 and not = 100 since solving for = 100 gives a fractional # and socks cannot be fractional). That being said, solving the above 2 equations give a = 6.33. So if the total cost is < 100, a can only go up since a is cheaper. so a > 6.33 but we are looking to see if a > 8 (again i am assuming most means > half). Statement #1 is not sufficient.
Statement #2 gives 6a + 9b < 120. Solving for this with a+b = 16 gives a=8. Since a is cheaper, and the total cost is < 120, a has to be greater than 8. So b is sufficient.

Is the OA B?

great question.

[cliq]

Yup . you have arrived at the right answer.

Originally Posted by kssshah

Interesting question. The way information is laid out does not give the confidence that what you assume is correct.

Didn't get you ?

[kssshah]

well, i was not sure if statement 1 i.e. 'He paid for the socks with a $100 bill.' meant he paid exactly $100 or < $100.

Also, in the question 'Were most of the pairs marked down by 40%?' - what "most" meant. I took it to mean more than half.

[cliq]

Thanks for clarifying. Your assumption in both the cases was correct.

[Gizmo]

That was a great question.

[gemini555]

A twisted question...pls explain

1. How did you arrive at 4.8a+7.2b? Please explain how you get the numbers

Thanks

[kssshah]

So the price of a pair of sock is $10. If there is a 40% discount, the price is $6. For the employee, there is 20% discount on $6 which would bring the price down to $4.8. If the offered is 10%, then the price is $9 and for employees, there is 20% discount on $9 i.e. $7.2. Hope this helps.

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