Math Olympiad #30 Homework Hints

1. How frequently do 3 or 7 appear as the units digit in the sequence of natural numbers?

2. When 4 coins are taken out of the pocket, how many are left in the pocket?

3. How many complete turns will the front wheel make in traveling 1 mile?  the rear wheel?

4. What values can C have?  Try one value and find the values of A and B that are then determined.  If the 3 values of A, B, and C do not satisfy the problem, try another value for C.

5. Work backward.