A computer monitor is composed of a large number of points of light calledpixels, It is not uncommon for a few of these pixels to be defective.Let X represent the number of defective pixels on a randomly chosen monitor. The probability distribution of X is as follows (table is below)

k 0 1. 2. 3

p(x=k) 0.2 0.5 0.2 0.1

Find the(2).