Question

1st TERM OF AN AP IS 'a' AND 18th TERM IS 'b'.WHAT IS THE 10th TERM

Answer 1

Hey !!!

1st term of an Ap is is a

t1 = a --------1)

t18 = b

let the first term of an Ap is a'

•°• tn = a' + (n - 1 ) d

t18 = a'+ (18- 1) d

t18 = a' + 17d

b = a' + 17d ---------2)

substracting equation 1 from 2

t18 - t1 = a' + 17d - a'

b - a = 17d

b - a /17 = d

Here we got first term = a

d = b - a /17

n = 10

hence , t10 = a + 9d

t10 = a + 9×(b-a/17)

t10 = 17a + 9b - 9a

t10 = 8a + 9b Answer ✔

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Hope it helps you !!!

@Rajukumar111