Q- Sum of 20 even numbers?

1.	Q- Sum of 20 even numbers?
Answer» ??Yogita<br>420<br>We have to find the sum n terms of the AP\xa02,4,6,...Here\xa0a=2,d=4−2=2.Therefore, Required sum\xa0Sn\u200b=n/2 \u200b[2a+(n−1)d]=n/2 \u200b[2×2+(n−1)×2]⇒Sn\u200b=n[2+n−1]⇒Sn\u200b=n(n+1) ...(1)Put\xa0n=20\xa0in (1), we getS20\u200b=20(20+1)=420

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