Well then let's try and find the pattern!
When we add 1 through 10, we can also say that we're adding all of these values together:
1 + 10 = 11
2 + 9 = 11
3 + 8 = 11
4 + 7 = 11
5 + 6 = 11
So we can also say that this is like multiplying 11 * 5 = 55
If we add up to 100, we can see that it's like multiplying 101 * 50 = 5050
From this, we can get an equation:
(x + 1) * (x/2)
So let's plug in 10000 into this equation:
(x + 1) * (x/2)
(10000 + 1) * (10000/2)
10001 * 5000 = 50005000
Answer:
C 50005000