The formula C(n, r) calculates the total number of ways of picking r objects out of n.
The formula works as follows:
[tex]C(n, r)= \frac{n!}{r!(n-r)!} [/tex]
where n! is 1*2*3*...*(n-1)*n
So, we calculate C(150, 4), which will give us the total number of ways we can make the selection of the computers.
[tex]C(150, 4)= \frac{150!}{4!(150-4)!}=\frac{150!}{4!146!}= \frac{150*149*148*147*146!}{4!*146!}= \frac{150*149*148*147}{4!}[/tex]
[tex]= \frac{150*149*148*147}{4*3*2*1}= 20,260,275[/tex] many ways.
Answer: 20,260,275
