Here a = -11 , d = 3 , Let the nth term be the first positive term.
nth term = a + (n-1) * d
n th term = -11+(n-1)*3 = -11+3n-3 = 3n-14, By Trial and error method we will put the value of n as 1, 2 and 5
By putting n=1 we get the value of nth term = 3*1-14 = -11 ( -ve term)
By putting n =2 We get 3*2-14 = 6-14 = -8
Now n = 5 we get 3*5-14 = 15-14 = 1 ( positive term) so the 5th term would be positive and the value would be 1.
Cheers Manjari!!!!!!!!!!!!