Objective function:

Maximum 0.5 * x1+0.4 * x2+0.6 * x3+0.5 * x4+0.9 * X5+1* X6.

Constraint function:

x 1 & lt； = 5

x2 & lt= 2

x3 & lt= 6

x4 & lt= 4

x5 & lt= 6

x6 & lt= 8

∑xi=22

Xi & gt； = 0，i = 1，2，3，4，5，6