Hard Sat math question- more like a weird one?

spuding102
Sun, 07 Apr 2013 16:26:12 +0000

Let S be the set of positive two digit integers in which the first digit is greater than the second digit. For example, 63 is a member of S, but neither 36 nor 33 is a member of S. How many integers are contained in S?

why is it not 45?

10,
20 21
30 31 32
40 41 42 43
50 51 52 53 54
60 61 62 63 64 65
70 71 72 73 74 75 76
80 81 82 83 84 85 86 87
90 91 92 93 94 95 96 97 98