Given that (12 + 22 + 32 + ..... + 202) = 2870, the value of (22 + 42 + 62 + ... + 402 ) is :

Answer: Option C

= (2² +4² +6² + ..... + 40²)
= (1 × 2)² +(2 × 2)² +(2 × 3)² + ..... + (2 × 20)²
= 2² × (1² + 2² + 3² + ..... + 20²)
= (4 × 2870)
= 11480