here are some questions appeared on the competition:
19. Which of the following sets of coordinates indicates a function?

a. (1,2)(1,3)(1,0)
b. (2,0)(9,10)(1000/500,3)
c. (2,1)(-2,12)(3,-2)
d. (1.6,8)(16,8)(1 3/5,8)
e. None of the above

20. What is the least whole number for which 3x>10?

a. 3 1/3
b. 3
c. 4
d. 30
e. None of the above

23. How many natural numbers are between (5)^1/2 and (10)^1/2?

a. 5
b. 6
c. 4
d. 1
e. None of the above
Can anyone solve at least one? I'm not sure if I got it right on these.