Hi,
In how many ways a delegation of 4 students can be selected from a group of 12 if 2 students refuse to be selected at the same time?
My solution was to calculate the nbr of ways 4 students can be selected from 12 (4C12 = 12! / 4!(12-4)! = 450 way) then subtracting it from the nbr of ways in which the 2 students (e.g. A & B) are selected together. The way I solved it was (2C12 = 12! / 2!(12-2)! = 66) but the solution was 2C10 and not 2C12?
Can anybody help me and explain why 2C10 and no 2C10?
In how many ways a delegation of 4 students can be selected from a group of 12 if 2 students refuse to be selected at the same time?
My solution was to calculate the nbr of ways 4 students can be selected from 12 (4C12 = 12! / 4!(12-4)! = 450 way) then subtracting it from the nbr of ways in which the 2 students (e.g. A & B) are selected together. The way I solved it was (2C12 = 12! / 2!(12-2)! = 66) but the solution was 2C10 and not 2C12?
Can anybody help me and explain why 2C10 and no 2C10?
I forgot that we should select 4 and not 2 members!!
