For an AP, the sum of the first 10 terms is equal to sum of the first 30 terms. Sum of m terms is equal to zero, what can be a possible value of m?
Sp =Sq
Sp+q= 0
S 40 = 0
2nd method: -
10a + 45d = 30a + 435d => 20a + 390d = 0
40a + 780d = 0
S40 = 0.