Question

Ryan needs to choose out of the 5 chores for afterschool. If he is equally likely to choose the chores,what is the probability he will choose the first 2 on list

Answer 1

Answer: 0.2

Explanation:

Number of ways to select r things out of n things =
`^nC_r=(n!)/(r!(n-r)!)`

Then , Total number of ways to select 2 out of 5 chores =
`^5C_2=(5!)/(2!3!)=(5*4*3!)/(2*3!)=10`

Number of ways to selecting first 2 on list = 2 (either he choose top on the list first then second , or second person first then topper)

Now , the probability he will choose the first 2 on list =
`(2)/(^5C_2)=(2)/(10)=0.2`

Hence, the probability he will choose the first 2 on list is 0.2.