JEE Main201912 Jan 2019Evening ShiftMathematicsBinomial TheoremActual
The total number of irrational terms in the binomial expansion of 7 1 5 - 3 1 10 60 is
Options
- A48
- B55
- C54
- D49
Correct answer
C. 54
Step-by-step solution
General term is   60 C r 7 1 5 60 - r - 3 1 10 r We will get rational term when r is multiple of 10 and 60 - r is multiple of 5 . ∴ r = 0 ,   10 ,   20 ,   30 ,   40   , 50 ,   60 ∴ Number of irrational term = Total terms - Number of rational terms = 60 + 1 - 7 = 54 .