Question

Kristen's financial advisor has given her a list of 8 potential investments and has asked her to select and rank her favorite four. In how many different ways can she do this?There are different ways Kristen can rank the four investments(Type a whole number)Help Me Solve ThisView an ExampleGet More HelpClear AllCheck Answer

Answer 1

Answer:

70 ways

Explanation:

This problem bothers on combination. According to combination formula;

$nC_r=\frac{n!}{(n-r)!}$

If Kristen's financial advisor has given her a list of 8 potential investments and has asked her to select and rank her favorite four, this can be expressed as;

$\begin{gathered} 8C_4=\frac{8!}{(8-4)!4!} \\ 8C_4=\frac{8!}{4!4!} \\ 8C_4=\frac{8\times7\times6\times5\times4!}{4!\times4\times3\times2} \\ 8C_4=\frac{8\times7\times6\times5}{24} \\ 8C_4=\frac{1680}{24} \\ 8C_4=70\text{ways} \end{gathered}$

Hence the number of different ways Kristen can rank the for investments is 70 ways