if in an A.P. ,a= 15,d= (-3) and an = 0, then find the value of n

1.	if in an A.P. ,a= 15,d= (-3) and an = 0, then find the value of n
Answer» Firstterm (a) = 15Common difference (d) = -3Last term (an) = 0tn=a+(n-1)d0=15+(n-1)-315=-3n+33n=15+3n=18/3n=6

Discussion