Divide the 9 numbers whose sum is 45 into two groups A and B. If the number "4" in group A is moved to group B, the average numbers of the two groups of numbers A and B are 0.25 larger than the original. How many numbers are there originally in group A?
将和为45的9个数分成A、B两组，如果将A组中的数"4"移到B组中，则A、B两组数的平均数都比原来大0.25．求A组中原来有多少个数？
<result>7</result>