The 10th and 18th terms of an A.P. are 41 and 73 respectively. Find 26th term.
a10 = 41
a + (10 – 1)d = 41
a + 9d = 41 …(i)
a18 = 73
a + (18 – 1)d = 73
Substituting the value of a from (i),
41 – 9d + 17d = 73
8d = 32
d =4
a = 41 – 9(4)
a =41 – 36
a =5
a26 =a + (26 – 1)d
=5 + 25(4)
=5 + 100
=105