JEE Main202226 Jun 2022Evening ShiftMathematicsBinomial TheoremActual
If C 0 40 + C 1 41 + C 2 42 + ⋯ + C 20 60 = m n × C 20 60 where m & n are co-prime, then m + n is equal to
Correct answer
0
Step-by-step solution
We know C r - 1 n + C r n = C r n + 1 Also C 0 40 = C 0 41 So C 0 41 + C 1 41 + C 2 42 + … . C 20 60 = C 1 42 + C 2 42 + C 3 43 . . . . C 20 60 = C 2 43 + C 3 43 + … C 20 60 = C 19 60 + C 20 60 = C 20 61 Given C 20 61 = m n C 20 60 ⇒ C 41 61 = 61 41 C 40 60 ⇒ 61 41 C 20 60 = m n C 20 60 ⇒ 61 41 = m n   ⇒ m + n = 102