1. There are 50 students attending the party, the first girl to arrive shook hands with all the boys, the second girl to arrive only missed shaking hands with 1 boy, the third girl to arrive only missed shaking hands with 2 boys, and so on, the last girl to arrive only shook hands with 7 boys, how many boys are there among the 50 students?
1. 28 boys 2. A total of 197 3. Can count to 10 continuously 04 . A total of 541 ways 5. The first class students walked $\frac{1}{7}$ of the total distance 6.17,901
1.【Solution】We can imagine each girl dancing with the last boy she shook hands with, and not shaking hands with anyone else. This way, after each pair of dancers leaves, the last 6(=7-1) boys remain, so there are 6 more boys than girls. By the method of solving sum and difference problems, we immediately get that the number of boys is $(50+6) \div 2$ $=28$.