The sum of all positive integer divisors of 6^2 = 36 is 1 + 2 + 3 + 4 + 6 + 9 + 12 + 18 + 36 = 91.

a) Determine a nice, closed formula (i.e., without dots or the summation symbol) for the sum of all the positive integer divisors of 6^????. 

b) Repeat for 12^????.

 c) Generalize.

2.Using the integers 1, 2, 3, 4, 5, 6 two players alternate in selecting numbers, one at a time, until the sum reaches 50. The winner is the person who first reaches exactly 50. Describe a winning strategy.

3.The intersecting circles have radii 6, 4, 4, and 2. How does the unshaded area inside the largest circle compare with the unshaded area outside the largest circle that is inside the small circles, assuming that the small circles are disjoint?