In the 13 cricket players 4 are bowlers, then how many ways can form a cricket team of 11 players in which at least 2 bowlers included:

The number of ways can be given as follows: 2 bowlers and 9 other players 

${=}^4{C}_2{\times }^9{C}_9$ , 3 bowlers and 8 other players ${=}^4{C}_3{\times }^9{C}_8$ bowlers and 7 other players ${=}^4{C}_4{\times }^9{C}_7$ 

Hence required number of ways

$=6\times 1+4\times 9+1\times 36=78$