For sum of first 11 terms of the progression
we can use the formula:
n/2(2a+(n-1)d)
which will give us the value
50=2a+10d
also sum of progression is:
n/2[first term + nth term)
by that:
a1+a11=50
since it is mentioned in the question that the difference common difference d and the first term should be an integer then we can conclude that a1=5 and a11= 45 and the common difference d= 4 so the next term ie. a12 should be 49 so our answer here is 275+49=324
answer choice : D
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