Question

if 10th and 18th term of arithmetic progression are 41 and 73 . find out the number of 27th term of an arithmetic progression​

Answer 1

Answer:

a27 = 109

Step-by-step explanation:

a10 = 41, a18 = 73

a27 = ?

an = a + (n-1)d

a10 = a + (10-1)d

41 = a + 9d

a + 9d = 41 ________(1)

an = a + (n-1)d

a18 = a + (18-1)d

73 = a + 17d

a + 17d = 73 _________(2)

Solving equations 1 and 2

a + 9d = 41

a + 17d = 73

= -8d = -32

= d = -32/-8 = 4

Putting value of d in eq 1

a + 9d = 41

a + 9×4 = 41

a + 36 = 41

a = 5

a27 = a + (n-1)d

a27 = 5 + (27-1)4

= 5 + 26×4

= 5 + 104

= 109