a=7
a+9d = 2(a+d)
Solve for a and d.
Now, since a sum requires two addends, I do not know what "the sum of the 28th term" is supposed to be. But, if you meant the sum of the first 28 terms, then
S28 = 28/2 (2a+27d)
So plug and chug.
Given that the first term of A.P is 7 and 10th term is twice the second term,calcute the sum of 28th term ?
1 answer