Zada has to distribute 15 chocolates among 5 of her children Sana,Ada,Jiya,Amir and Farhan .She has to make sure that Sana gets at least 3 and at most 6 chocolates . In how many ways can this be done if child gets at least 1 chocolate

425?<br>This is the concept of pnc in which we distribute similar objects to diff <br>in case 1 when 3 chocolate is given to one person and rest 12 are left. a+b+c+d=12. but a>=1, b>=1, c>=1, d>=1. hence, a+b+c+d=8. 11c3 ways. similarly for other 3 cases.