Math Olympiad Hints

OLYMPIAD 25 Hints:

1.  In what digit must the multiple of 7 end to satisfy the condition of 
divisibility of 5?

2.  Let the 6 people be A,B, C, D, E, and F.  Make a list of the different 
matches played in the first round.

3.  10 x 10 = 100; 20 x 20 x 20 = 8000; 30 x 30 x 30 = 27,000.  Between which 
two products is 15,600 increased?

4. If the average of all three numbers is 1, what must their sum be?

5. If a number is divisible by 36, it is also divisible by 4 and 9.  What 
digits can B be?