Question

(xi) The sum of first 20 term sof the AP; 1,3,5,7,
9,....is​

Answer 1

Answer:

400

Step-by-step explanation:

Here a=1,n=20

then l=(2×n)-1=2×20-1=39

So, Sn=(n/2)×(a+l)=(20/2)×(1+39)=10×40=400

Hope it will help you .

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