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Question
Which term of the A.P. 3, 8, 13, ... is 248?
Solution
Here, A.P is 3, 8, 13,....
`a_n = 248`
a = 3
Now
Common difference (d) = `a_1 - a`
= 8 - 3
= 5
Thus, using the above mentioned formula
`a_n = a + (n - 1)d`
248 = 3 + (n - 1)5
248 - 3 = 5n - 5
245 + 5 = 5n
`n = 250/5`
Thus n = 50
Therefore 248 is the 50th term of the given A.P
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