2012 A

[smeag]

please help on: 29, 33, 49, 51, and 59

[DentonKnight]

29. All factorials greater than or equal to 10! have two zeros in the tens and units places. So the problem simplifies to:
1 + 1 + 2 + 6 + 120 + 40320 = 40450, so the answer is B, 5.
49. (d-1)/(d+n - 1) = .2
(d)/(d+n -2) = .25
then solve the system.
51. All of the numbers in the set summed with another element of the set equal a third element except 11. All of the other numbers except 2 and 7 have two elements that they sum with to form another element (2 has 1, 7 has 1). Also, the first and second elements can't be the same. So 1/2 * 2/5 + 1/6 * 1/5 + 1/6 * 1/5 = B.
59. BD = 61^1/2 by Pythagorean theorem. AB = 10 by same theorem. Then use Heron's area of a triangle formula.

[nsguy1350]

For 33, you have 110%, 105%, 112%, and 92%. Take the geometric mean of these to get average.