Math Chapter Wise Permutation And Combination English MCQ PGT 2010 Q.If 1 36, 84 − − = n n r r C C and 1 126 + + = n r C then An= 8, r = 4 Bn= 9, r = 3 Cn=1, r =5 DNone of these Show answer Correct answer: n= 9, r = 3