Ten DS questions for discussion today

[neilcao]

Q1.the tens digit of number N?
D1. 10n hundreds digit is 2.
D2. n-9 tens digit is 1.

Q2. Someon is making a cake. Part of the cake is given to his company, and another part is given to his neighbor, he keeps the remaining part. Is the part he keeps 1/3 of the total?

D1. The part he keeps is less than those give to his company and those given to his neighbor.
D2. The part given to his company is 50% of the total.


Q3. If A is $23 each B is $20 each, the number purchased for each?
1) Total cost is $169
2) Purchased three A


Q4. How many people are Certified Public Accountant?
1) 2/3 are men and 60%of whom IS CPA.
2) 1/3 are women


Q5. Is 1+x+x^2+x^3+x^4 >1/（1-x）?
D1. x>0
D2. x<1


Q6. Find x^2+y^2-z^2-2xy = ?
D1. y+z=x
D2. x+z=y


Q7. P and S are all integer. when q is divided by p, the remaining is q/2 Find q?
（1）q is prime number
（2）q<17


Q8. A number of people make choices, there are two choices A and B. Will half of the people make the same choice twice, i.e. First round=A, second round= A
D1. For the first round, more than half chose A
D2. For the second round, more than half chose B

Q9. Probability for A to occur or B to occur or both AB to occur is 0.6. Can we determine the probability for A to occur only but not B
D1. The number for for both AB's occurring rate is the same.
D2. The probability for none of A or B to occur is 0.4


Q10. Can N become the difference between two prime numbers?
D1. N=11
D2. （N-7）（N-11）=0

[Anurag@Gurome]

Please post them in different threads.
It's very painful for readers to browse through ten solutions at a time. Also check the wordings of the problems.