The manager of a stockroom in a factory has constructed the following probability distribution for the

daily demand for a particular tool:

y	0	1	2
p(y)	0.1	0.5	0.4

where y is the number of times the tool is used in one day. It costs the factory $10 each time the tool is used. Define c(y) to be the daily cost for use of the tool.

(i) Find the mean of the daily cost for use of the tool.

(ii) Find the variance of the daily cost for use of the tool.