Answer: Choice A
(5C3)*(7C4)*(9C2)
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Step-by-step explanation:
We have 5 applications for math teachers, but only 3 slots to fill. Order does not matter, so there are 5C3 different combinations possible. The C refers to the combination formula as shown below
![_nC_r = (n!)/(r!(n-r)!)](https://img.qammunity.org/2021/formulas/mathematics/college/l7gxnlcam0jpp17tewivmd9vo41ya8oh1e.png)
Similarly, we have 7 science teacher applications, and 4 slots to fill. There are 7C4 different combinations here.
Lastly, there are 9 English teacher applications and 2 slots to fill giving 9C2 ways to do this.
We then multiply out those three expressions getting the final answer shown in choice A.