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

Step-by-step explanation:

Number of ways to select r things out of n things = $^nC_r=\dfrac{n!}{r!(n-r)!}$

Then , Total number of ways to select 2 out of 5 chores = $^5C_2=\dfrac{5!}{2!3!}=\dfrac{5\times4\times3!}{2\times3!}=10$

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 = $\dfrac{2}{^5C_2}=\dfrac{2}{10}=0.2$

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