The 7th term of an arithmetic sequence is 34 and 15th term is 66 then what is the common difference

 

Solution 

Let a and d is first term and common difference of the AP.

According to Question,

  The 7 th and 15 th terms of an Ap are 34 and 66 .

Means, a7=34 & a15=66

now a7=34

a+ 6d=34.......(i)

&  a15=66

a+14d=66.........(ii)

From Equation(i) & (ii)

a+6d=34......(i)

a+14d=66........(ii)

after solving,

a=10

and d = 4

Hence common difference=4 ans.....