11² + 12² + 13² + … + 45²= ?
Show answer & explanation
Correct answer: D
Explanation
Given:
11² + 12² + 13² + … + 45²
According to the formula:
1² + 2² + … + n² = n(n+1)(2n+1)/6
Sum = (1² + 2² + … + 45²) − (1² + 2² + … + 10²)
= [45×46×91 / 6] − [10×11×21 / 6]
= (188370 / 6) − (2310 / 6)
= 31395 − 385
= 31010