Answer:
Cr = 10
Step-by-step explanation:
To calculate combinations we use the nCr formula: nCr = n! / r! * (n - r)!, where n = number of items, and r = number of items being chosen at a time.
![C(n,r)=[?]](https://tex.z-dn.net/?f=C%28n%2Cr%29%3D%5B%3F%5D)




[RevyBreeze]
Making the assumption that your problem looks like this,

we use the distributive property to multiply:
Will its 12.75 because you add 3+9 =12 and you just put the 75 that's it