Question

the 5th term of an as is 40 and 10th term of an as is 20 find 15th term​

Answer 1

0 is the answer I suppose

Answer 2

nth term of AP=a + (n - 1) * d

5th term of an AP = a + 4d = 40…………(1)

10th term of an AP = a + 9d = 20 ……………(2)

Solving (1) and (2) we get

a + 4d = 40

a + 9d = 20

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       d = 5

Substitute d = 5 in (1), we get

a + 4d = 40

a + 4(5) = 40

a = 40 - 20

a = 20.

Then:

15th term = a + 14d

                = 20 + 14(5)

                 = 20 + 70

                 = 90