Question

An agriculture researcher wants to test the effect of nine soil additives by adding four at a time to different rows of the same plant. How many different combinations can be tested?

Answer 1

i believe its 126 let me know if its right ^_^

Answer 2

126 combinations can be tested.

Explanation:

An agriculture researcher wants to test the effect of nine soil additives by adding four at a time to different rows.

We have to find the combination which can be tested.

Combinations formed can be written as
`^(9)C_(4)`

`^(9)C_(4)` =
`(9!)/((4!)(9-4)!)`

=
`(9!)/(4!5!)=(9* 8* 7* 6* 5!)/((4* 3* 2* 1)* 5!)`

=
`(9* 8* 7* 6)/(4* 3* 2* 1)` =
`(3024)/(24)=126`

therefore, 126 combinations can be tested.