Permutation and combination

Question

Comments

minal i'm stuck with gen functions too, i solved it by calculating number of non negative integral solutions

---

are you getting  my ans?

---

utkarsh ans is 126 only , i did calculation mistake

24c4-5c1*18c4 + 5c2*12c4 - 5c3*6c2 = 10626+4950-15300-150 = 126