Q24 of 39 Page 1

The first term of an AP is 3, the last term is 83 and the sum of all its terms is 903. Find the numbers of terms and the common difference of the AP.

Now, a = 3


l = 83


Sn = 903


We know,






⇒ 43n = 903


⇒ n = 21


As we know an = a +(n-1)d and an = l.


⇒ 83 = 3 + (21-1)d


⇒ 80 = 20d


⇒ d = 4


∴ Number of terms is 21 and the common difference is 4.


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