Analysis of test questions: (1) Assuming that each round of infection infects an average of X people, according to the fact that 64 people have influenza after two rounds of infection, X can be obtained.

(2) Then find out the number of reinfected people after the third round.

Analysis of test questions: (1) Assuming that each person infects an average of X people in each round of infection,

1+x+x(x+ 1)=64

X=7 or x=-9 (truncation).

A: In each round of infection, the average person is infected with 7 people;

(2)64×7=448 (person).

A: Another 448 people will be infected in the third round.