Two students decide to save money monthly in separate ways for a school excursion.
Plan X: The first deposit is Rs 200 and each following month the deposit increases by Rs 20.
Plan Y: The first deposit is Rs 150 and each following month the deposit increases by Rs 30.
(i) For each plan, write an expression for the total amount saved in the first n months.
(ii) In which month will the total amount saved under the two plans become equal for the first time?
(iii) How much will each student have saved by that month?