Current location - Training Enrollment Network - Mathematics courses - Chengdu Foreign Languages School solved four small problems in the mathematics test paper of the "Derui Cup" knowledge contest in 2008.
Chengdu Foreign Languages School solved four small problems in the mathematics test paper of the "Derui Cup" knowledge contest in 2008.
Assume that the number of people who correctly do 0, 1, 2, 3, 4 and 5 are x0, x 1, x2, x3, x4, x5 and x6 respectively.

Suppose *** 100 people.

X0+...+X5 = 100。

0 * x0+x 1+2 * x2+3 * x3+4 * x4+5 * X5 = 80+95+85+79+74;

3(x3+x4+X5)+x 1+2 * x2+x4+2 * X5 = 4 13

3(x3+x4+X5)= 4 13-(x 1+2 * x2+x4+2 * X5)

= 4 13-( 100-x0-x3-x4-X5+x4+2 * X5+x2)

=3 13-(x5-x0-x3+x2)

(x0+x3)+(x2+X5)& lt; = 100

get

3(x3+x4+X5)》= 3 13-( 100-2(x0+x2))》= 2 13

At least 7 1. 1