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 $\frac{i}{i}$.