Question
In How many ways can a student choose a program of 5
courses, if 9 courses are available and 2 courses are compulsory for every student?Solution
Total courses =9 Choose program =5 Total number of the way with two courses are compulsory- = 9 -2 C5-2 =7C3 
More Permutation and combination Questions
3,   2,   3,  8,  31,  ?
56. 23Â Â Â Â Â 45Â Â Â Â Â 89Â Â Â Â Â 177Â Â Â Â Â 363Â Â Â Â Â 705
...22Â Â Â Â Â Â Â Â Â Â 62Â Â Â Â Â Â Â Â Â Â 178Â Â Â Â Â Â Â Â 522Â Â Â Â Â Â Â Â 1550Â Â Â Â Â Â ?
...77 ? 190 257 331 412
...2, 12, 90, 240, ?, 1260
41 48 89 137 226 ?
...43 36 50 29 ? 22
...5 14 56 220 1125 6786
...7 29 ? 129 211 349
19 8 ? -14 63 - 36
...
