A) 1600
B) 1680
C) 420
D) 840
Correct Answer: B
Solution :
The given series \[2\times 4+4\times 6+6\times 8....\]\[{{n}^{th}}\] terms \[{{T}_{n}}=2n\ .\ 2(n+1)=4n(n+1)\] Putting\[n=20\], we get\[{{T}_{20}}=4\ .\ 20(20+1)=1680\].You need to login to perform this action.
You will be redirected in
3 sec