Q1 of 110 Page 53

Find the sum of the first (i) 75 positive integers (ii) 125 natural numbers.

(i) In the A.P.


First term = 1


No. of terms = 75


Common difference = 1


Sum of terms =


⇒ Sum of terms =


⇒ Sum of terms =


⇒ Sum of terms = 2850


(ii) In the A.P.


First term = 1


No. of terms = 125


Common difference = 1


Sum of terms =


⇒ Sum of terms =


⇒ Sum of terms =


⇒ Sum of terms = 7875


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