A) 2250
B) 2500
C) 2525
D) 3775
Correct Answer: B
Solution :
\[1+2+3+.............+x=\frac{x(x+1)}{2}\] \[\therefore \] \[1+3+5+.............99\] \[=(1+2+3+4+5+......100)\] \[-(2+4+6+......100)\] \[=\frac{100(100+1)}{2}-2(1+2+3+....50)\] \[=\frac{100\times 101}{2}-\frac{2\times 50\times 51}{2}\] \[=50\times 101-50\times 51\] \[=50(101-51)\] \[=50\times 50=2500\]You need to login to perform this action.
You will be redirected in
3 sec