Q>The sum of n terms of two arithmetic progressions are in the ratio (3n+8): (7n + 15). Find the ratio of their 12th terms.
Note : I am already aware of the method wherein we subsitute 'n=23'.
But i have done this question with a different method and I am getting a wrong answer , please help me find the error. ( image ATTACHED)
Why cant we take the ratio of sum of 'n' terms as the absolute value of the sum of 'n' terms?
Where are exactly things going wrong???
Your help will be highly appreciated ???
Note : I am already aware of the method wherein we subsitute 'n=23'.
But i have done this question with a different method and I am getting a wrong answer , please help me find the error. ( image ATTACHED)
Why cant we take the ratio of sum of 'n' terms as the absolute value of the sum of 'n' terms?
Where are exactly things going wrong???
Your help will be highly appreciated ???