Respuesta :

For choose notation, you...
xCy = x! / (x-y)! y!
! means factorial

(28 x 27 x 26...x 3 x 2 x 1)/(14 x 13 x 12...x 3 x 2 x 1)(14 x 13 x 12...x 3 x 2 x 1) = 40116600