Remember that
the formula to calculate the combination is equal to
nCr=n!/[r!(n-r)!]
in this problem
we have
n=4
r=3
substitute the given values
4C3=4!/[3!(4-3)!]
4C3=4!/[3!(1)!]
4C3=4*3!/3!
4C3=12
the answer is 12
For 2 scoops
we have
n=4
r=2
substitute
4C2=4!/{2!(4-2)!]
4C2=(4*3*2*1)/4
4C2=6
the answer is 6
