Question

The sum of the third and the ninth term of an AP is 10. Find a possible sum of the first 11 terms of this AP.​

Answer 1

Answer:

44

Explanation:

The third term t3 = a + 3d

The ninth term t9 = a + 8d

t3 + t9 = 2a + 10d = 8

Sum of first 11 terms of an AP is given by

⇒S11=$\frac{11}{2}$[2a+10d]

⇒S11=$\frac{11}{2}$×8

⇒S11=44