The sum of the first 7 terms of an A.P. is 10, and that of the next 7 terms is 17. Find the progression

Assuming the first term as a and common difference as d

To find: the progression


So, the sum of first 7 terms is given by


a + a + d + a + 2d + a + 3d…. a + 6d = 10


7a + 21d = 10…(i)


In the second part it is given that sum of next seven terms is 17


a + 7d + a + 8d + a + 9d…. a + 13d = 7


7a + 70d = 7…(ii)


Solving (i) and (ii) we get


10 - 21d = 7 - 70d


3 = - 49d




Hence the sequence is given by a, a + d, a + 2d…. which is



17