Question 503184

{{{(n!)/(r!(n-r)!)}}}


{{{(10!)/(3!*(10-3)!)}}}


{{{(10!)/(3!*7!)}}}


{{{(10*9*8*7!)/(3!*7!)}}}


{{{(10*9*8*highlight(7!))/(3!*highlight(7!))}}}


{{{(10*9*8*cross(7!))/(3!*cross(7!))}}}


{{{(10*9*8)/(3!)}}}


{{{(10*9*8)/(3*2*1)}}}


{{{(720)/(6)}}}


{{{120}}}


So there are 120 different groups.