The average of 101 consecutive odd numbers is 303. Find the largest number. |
373 401 403 409 |
403 |
Assume, First odd number = (2n+1) 2nd odd number = (2n+1) + (2-1)(2) = 2n + 3 3rd odd number = (2n+1) + (3-1)(2) = 2n + 5 Similarly, Last (101th) odd number = (2n+1) + (101-1)(2) = 2n + 201 This is an Arithmetic progression, Thus its sum Sn = (N/2) (a+L) Sn = (101/2) (2n+1 + 2n+201) = (101/2) (4n+202) = 101(2n+101) Average = Sum/101 303 = 101(2n+101)/101 2n+101 = 303 n = 101 Last Term L, 101th term = 202+201 = 403 The correct answer is Option (3) → 403 |