Question

The 17th term of an AP exceeds its 10th term by 7. Find the common difference.NCERT Class XMathematics - MathematicsChapter _ARITHMETIC PROGRESSIONS

Answer 1

It is given that,
=> a17=a10+7

We know that [an=a1+(n-1)d], where 'd' is the common difference

Expand a17 and a10
=>a1+16d=a1+9d+7
=>7d=7
=>d=1

Therefore the common difference is 1

Answer 2

Solution :

Let a be the first term and d the common difference.

It is given       $a_{17} - a_{10} = 7$

⇒ (a + 16d) - (a + 9d) = 7

⇒                          7d = 7  

⇒                            d = 1

Thus, the common difference is 7.