If n and r are non-negative integers and n≥r, then p(n + 1, r) equals to
A. P(n,r)(n+1) / (n+1-r)
B. P(n,r)(n+1) / (n-1+r)
C. p(n,r)(n-1) / (n+1-r)
D. p(n,r)(n+1) / (n+1+r)
Answer:A
If n and r are non-negative integers and n≥r, then p(n + 1, r) equals to
A. P(n,r)(n+1) / (n+1-r) B. P(n,r)(n+1) / (n-1+r) C. p(n,r)(n-1) / (n+1-r) D. p(n,r)(n+1) / (n+1+r)