Question

The sum of first n terms of a A.P. is 100 and sum of first n terms of an other A.P. is 300. Find the ratio of common difference:

• A. 1:6
• B. 1:3
• C. 1:1
• D. cannot be determined

Answer 1

The correct option is D

cannot be determined

If sums of the series are in ratio 1:3, then the ratio of common difference will remain same.

For example: Let an A.P. 18, 19, 20, 21, 22 , an other one 58, 59, 60, 61, 62 and an other A.P. 54, 57, 60, 63, 66 sum of first A.P. =100 and sum of others A.P. = 300. So, the ratio of common difference = 1: 1 and 1 : 3.Option (d).