Four of a sample of 150 computers will be selected and tested. how many different ways are there to make this selection?

The formula C(n, r) calculates the total number of ways of picking r objects out of n.

The formula works as follows:



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.



many ways.

20,260,275

Think of it as five or above give it a shove. change the 5 or above to the right to a zero and add one to the number on the left.