Six questions from Princeton GMAT Math Bible

[amyyoung999]

I just purchased the princeton GMAT Math Bible.Please help me solve the following questions.

8. In how many ways can five people sit around a round table?

11. Whether point A(r, s) is on the line y=2x+3?
（1）(2r-s+3)(4r+2s-6)=0
（2）(3r+2s-5)(2r-s+3)=0

17. m is a two-digit number and 2m is a three-digit number, what is the unit digit of m?
（1）the unit number of 2m is 4;
（2）the unit number of m is the same as the tens number of 2m；

30. When a number is divided by 13, the quotient is k, the remainder is 2; when it was divided by 17, and the remainder is 2. What is the remainder of K divided by 17?
6.
（1）X>0
&#65288;2&#65289;X<1

13. Put two keys in a key ring which already has five keys. What is the probability that the two new keys will be together?



Thanks a lot.

[gabriel]

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