I think it’s c. Not sure though. Pure guess
Answer:
Jaylon has completed 12 problems.
Step-by-step explanation:
(This is how I learned it- I'm not sure if you have been taught this way..)
Step 1. Set up a proportion

Step 2. Do 200x 60 to get 1200
Step 3. Get this equation

Step 4. Get the answer of 12
I hope this helps! :)
The answer is B. 120
nCr = n! / ((r! * (n - r)!)
n = 10
r = 3
10C3 = 10! / ((3! * (10 - 3)!)
= 10! / ((3! * 7!)
= (10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1) / (3 * 2 * 1 * 7 * 6 * 5 * 4 * 3 * 2 * 1)
= 3628800 / 30240
= 120