A question paper has 2parts, A & B, each containing 10 questions. If a student has to choose 5 from part A &10 from part B, in how many ways can he choose the questions?  Choose the correct choice from the following:
A) 100
B) 120
C) 125
D) 350
E) 252
There 5 questions in part A out of which 10 question can be chosen as = 10C5   Similarly, 10 questions can be chosen from 10 questions of Part B as = 10C10.   Hence, total number of ways,   =10C5*10C10   =[10!/(5!5!)]*[10!/(0!*10)]   = {10*9*8*7*6/(5*4*3*2*1)}* 10!/1*10!   = 252   252
<result>E</result>
A question paper has 2parts, A & B, each containing 10 questions. If a student has to choose 5 from part A &10 from part B, in how many ways can he choose the questions?