Mathematics
In an A.P. a = -36, d = 18 and l = 36, then n is :
10
5
15
20
AP GP
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Answer
Let nth be the last term.
By formula,
an = a + (n - 1)d
Substituting values we get :
⇒ 36 = -36 + (n - 1)18
⇒ 36 = -36 + 18n - 18
⇒ 36 + 36 + 18 = 18n
⇒ 18n = 90
⇒ n = = 5.
Hence, Option 2 is the correct option.
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