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Question
The first three terms of an A.P. respectively are 3y − 1, 3y + 5 and 5y + 1. Then, y equals
Options
- 3
4
5
2
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Solution
Since, 3y − 1, 3y + 5 and 5y + 1 are first three terms of an A.P.
Then, Second term − First term = Third term − Second term = d (common difference)
⇒ 3y + 5 − (3y − 1) = 5y + 1 − (3y + 5)
⇒ 3y + 5 − 3y + 1 = 5y + 1 − 3y − 5
⇒ 6 = 2y − 4
⇒ 2y = 6 + 4
⇒ 2y = 10
⇒ y = 5
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