Question

Evaluate the expression: 18_C_4Both the numbers are tiny like small and next to the C. A. 3,060B. 12,240C. 18,360D. 73,440

Answer 1

Given that you need to evaluate:

`_(18)C_4`

Therefore, you need to use the Combination Formula:

`_nC_r=(n!)/(r!(n-r)!)`

Where "n" is the total number of objects of a set and "r" is the number of objects chosen from the set.

In this case, you can identify that:

`\begin{gathered} n=18 \\ r=4 \end{gathered}`

Then, you can substitute values into the formula and evaluate:

`_(18)C_4=(18!)/(4!(18-4)!)`
`_(18)C_4=(18!)/(4!(14)!)`
`_(18)C_4=3060`

Hence, the answer is: Option A.