Answer: The students in the math interest group reached 75% in this competition.

(2) The total number of employees is 100;

Then the number of people who passed is:

100×35%+ 100×40%,

=35+40,

=75 (person);

The failure is:

100×25%=25 (person);

70× 100-80×75,

=7000-6000,

= 1000 (minutes);

1000÷25=40 (point);

A: The average score of students who failed is 40.

So the answer is: 75,40.