1.10个.2.平均成绩最高为89.6分,最低为80.2分.3.设第2列的捐款额为x元,第3列的捐款人数为y.由题意得3×8+15x+7y+10×12=338.化简,得15x+7y=194.这个二元一次方程的整数解有x=5 y=17,和x=12 y=2,但y=2时全班人数少于50,不合题意,所以只能取x=5 y=17.4.把10从A组移到B组后,A组中各数的平均数变大了,所以我们不妨先假设原来A组中的数为10至30,B组中的数为0至9,然后逐步调整可得A组中原有21个数,其平均数是 1.10 2. The highest average score is 89.6 points and the lowest is 80.2 points. 3. The donation amount in column 2 is x yuan and the donation number in column 3 is y. The question score is 3 × 8 + 15x + 7y + 10 × 12 = 338. Simplify to get 15x + 7y = 194. The integer solution to this binary equation has x = 5 y = 17 and x = 12 y = 2, but y = 2 At 50, not in the way, so we can only take x = 5 y = 17.4. After moving 10 from group A to group B, the average of each number in group A becomes larger, so we may first assume that the original group A The number of 10 to 30, the number of B group is 0 to 9, and then gradually adjust the original available 21 in the A group, the average is