62. Exemplar exercise problem XXII

The ratio of the $11^{th}$ term to the $18^{th}$ term of an AP is $2 : 3$. Find the ratio of the $5^{th}$ term to the $21^{st}$ term, and also the ratio of the sum of the first five terms to the sum of the first $21$ terms.

 

The ratio of $a_{5}$ to $a_{21}$ is $\frac{i}{i}$ .

 

The ratio of $S_{5}$ to $S_{21}$ is $\frac{i}{i}$.