20 hardest questions posted in 2015 in descending order

1. If a circle passes through points (9,2*sqrt(3))
2. If x, y and z are positive integers such that x^4*y^3 = z^2
3. Abe, Beth, Carl and Duncan are four siblings, among which Abe and Carl
4. Daniel is playing a dice game in which a dice is rolled 5 times
5. P and Q are prime numbers less than 70. What is the units digit of P*Q
6. How many different pairs of integers (a, b) exist such that 2 <= a <=
7. Allen starts from X, goes to Y. At the same time Bob starts from Y and
8. If a, b and n are positive integers such that n = 3a ? b3
9. In the xy-coordinate plane, line L passes through the points (b, a) an
10. If a and b are positive integers larger than 1, is a^b > b^a?
11. The numbers D, N, and P are positive integers, such that D < N, and N
12. At 8am on Thursday, two workers, A and B, each start working independe
13. In the correctly-worked multiplication problem above, each symbol repr
14. Is (2a - b)(b - 3c) > 0?
15. Let a ?2-placer? be a terminating decimal, between 0 and 1, for which
16. Random Pack 1, Question 3 Three circles with radii...
17. In the trapezoid above, with sides a, b, c, and 1, what is the value o
18. When 120 is divided by single-digit integer m the remainder is
19. x@y = 2x^(1/2) + y^2. How many unique sums of x and y result, if x@y
20. Four friends go to Macy?s for shopping and buy a top each. Three of th

20 questions posted in 2015 with most kudos bookmarks

1. Two positive integers a and b are divisible by 5, which is their 22 kudos/bookmarks
2. If x, y and z are positive integers such that x^4*y^3 = z^2 20 kudos/bookmarks
3. Five identical pieces of wire are soldered together end-to-end to form 20 kudos/bookmarks
4. If a, b and n are positive integers such that n = 3a ? b3 19 kudos/bookmarks
5. Is the product of two integers A and B odd? 17 kudos/bookmarks
6. If positive integer N = A ? B, where A is a positive integer and B is 15 kudos/bookmarks
7. P and Q are prime numbers less than 70. What is the units digit of P*Q 15 kudos/bookmarks
8. The Prime Sum of an integer X greater than 1 is the sum of all prime 13 kudos/bookmarks
9. When positive integer x is divided by positive integer y, the result i 12 kudos/bookmarks
10. A line passes through point p(1,1) and q(100,1000). How many other poi 12 kudos/bookmarks
11. If a, b and n are positive integers such that n = 3a ? b3 11 kudos/bookmarks
12. The last digit of 12^12 + 13^13 ? 14^14x15^15 = 11 kudos/bookmarks
13. If 6 coins are tossed, how many different coin sequences will have exa 11 kudos/bookmarks
14. Set S is composed of following real numbers {1/96 , 2/96 , .. , 11 kudos/bookmarks
15. If x and y are positive numbers such that x + y = 1, which of the 10 kudos/bookmarks
16. How many different prime factors does positive integer n have? 10 kudos/bookmarks
17. IF N=5^5*..., then how many zeroes exist between decimal and first non 10 kudos/bookmarks
18. x^n = x^(n+2) for any integer n. Is it true that x > 0? 10 kudos/bookmarks
19. For all positive integers n and m, the function A(n) equals the follow 10 kudos/bookmarks
20. Two perpendicular chords intersect in a circle. The segments of one ch 9 kudos/bookmarks