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CBSE - Mathematics - Arithematic Progressions

Arithematic Progressions

NCERT Exercise Exercise 5.2

If 17th term of an A.P. exceeds its 10th term by 7. Find the common difference.

We know that,
For an A.P., an = a + (n − 1) d
a17 = a + (17 − 1) d
a17 = a + 16d
Similarly, a10 = a + 9d
It is given that
a17 − a10 = 7
(a + 16d) − (a + 9d) = 7
7d = 7
d = 1
Therefore, the common difference is 1.

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