CBSE 10th Class past year question paper
Year 2019
SET 1, Code Number- 30/2/1
Question number – 29 (a)
Deepak BoraNewbie
Which term of the Arithmetic Progression –7, –12, –17, –22, … will be –82 ? Is –100 any term of the A.P. ? Give reason for your answer.
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an = a + ( n – 1 ) d
∴ –82 = –7 + (n – 1) (–5)
15 = n – 1 or n = 16
Again,
–100 = am= –7 + (m – 1) (–5)
(m – 1)(–5) = –93
m – 1 = 93/5 or m = 93/5 + 1 ∉ N
∴ –100 is not a term of the AP.