What is the value of 14³ + 16³ + 18³ + ...+ 30³ ?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 ie 111672.
14³ + 16³ + 18³ + ...+ 30³
= 8(7³ + 8³ + 9³ + ...+ 15³)
Sum of n cubes = 
n = 6 = [(6 × 7)/2]² = 441
n = 15 = [(15 × 16)/2]² = 14400
Difference = 13959
S = 8 × 13959 = 111672