Tn = -91+(n-1)6
Positive terms: Tn>0
solving the inequality, we get
thus T1 to T16 are the negative terms
Given the number of positive terms = 3 times the negative terms
Number of positive terms = 3×16 =48
Total number of terms =48 + 16 =64
Sum of positive terms = T17 +T18 + …. T64 = S64 – S16.
Using the formula to find the sum of n terms in AP, u shld be able to get the solution.
Hope i got it correct.