Question 896969
a1=19, an=89 and Sn= 810
S = ½(a1 + an)n
810 = ½(19 + 89)n
810 = ½(108)n
810 = 54n
n=15
89 = 19 + (14)d
70=14d
d=5
19,24,29,34,39,
44,49,54,59,64,
69,74,79,84,89