Respuesta :
nPr = 6720
nCr = 56
we know
nCr = nPr/ r ! = 56
6720/r! = 56
r! = 6720/56 = 120
r! = 5×4×3×2×1= 5!
so r = 5
for 2nd part
its not possible because
nPr > nCr
nCr = 56
we know
nCr = nPr/ r ! = 56
6720/r! = 56
r! = 6720/56 = 120
r! = 5×4×3×2×1= 5!
so r = 5
for 2nd part
its not possible because
nPr > nCr