If 1² + 2² + 3² + ................... + 10²= 385, then what is the value of 2² + 4² + 6² + ......................+ 20²?

Question: If 1² + 2² + 3² + ................... + 10²= 385, then what is the value of 2² + 4² + 6² + ...................... + 20²?

Solution:
2² + 4² + 6² + .... + 20²
= 2² (1² + 2² + 3² +....+10²)
= 4 × 385
= 1540