-) - The 10th term and the 18th term of an A.P. are 25 and 41 respecti

1.	-) - The 10th term and the 18th term of an A.P. are 25 and 41 respectively thenfind 38th term of that A.P., similarly if nth term is 99. Find the value of n.
Answer» a10 = a + 9d = 41 .........(1)a18 = a + 17d= 72.........(2) (1) - (2) a - a + 9d - 17d = 41 -73 8d = 32 d = 4 a + 36 = 41 a = 5 then a26 = 5 + 25 × 4 = 5 + 100 = 105

-) - The 10th term and the 18th term of an A.P. are 25 and 41 respectively thenfind 38th term of that A.P., similarly if nth term is 99. Find the value of n.

Answer»

a10 = a + 9d = 41 .........(1)a18 = a + 17d= 72.........(2)

(1) - (2)

a - a + 9d - 17d = 41 -73

8d = 32

d = 4

a + 36 = 41

a = 5

then a26 = 5 + 25 × 4 = 5 + 100 = 105