Question
If a, b, c are three natural numbers in AP and a + b + c =21 then the possible number of values of the ordered triplet ( a , b , c ) is
BITSAT
Mathematics
Binomial Theorem
2020
BITSAT 2020
BITSAT Mathematics Question (2020) — Solution
Options
- A. 15
- B. 14
- C. 13
- D. None of these
Answer
C. 13
Step-by-step solution
Let a=b-d and c=b+d, then a+b+c=21 b =7 So, the equation is a + c =14 No. of solution = coeff. of x^ 14 in (x+x^ 2 + . ) = ^ 13 C _ 12 =13
Related: Mathematics — Binomial Theorem · All PYQ Banks