If $$(2n + 1) + (2n + 3) + (2n + 5) + ... + (2n + 47) = 5280$$, then whatis the value of $$1 + 2 + 3 + .. + n?$$
Correct Answer: 4851
Let us first find the number of terms
47=1+(n-1)2
n=24
24*2n+1+3+5+....47=5280
48n+576=5280
48n=4704
n=98
Sum of first 98 terms = 98*99/2
=4851
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