need help

\(\sum_{50}^{499}\)  2n+1 =247500

101 + 103 + 105 + ... + 995 + 997 + 999

This is an arithmetic sequence with     t₁ = 101     t_n = 999     d = 2

We can use the formula:  t_n  =  t₁ + (n - 1)d  to find the number of terms:

--->     999  =  101 + (n - 1)2     --->     n = 450

We can use the formula:  Sum  =  n(t₁ + t_n)/2  to find the sum of the terms:

--->     Sum  =  450(101 + 999)/2     --->     Sum  =  247 500