Question

In the following situations, do the lists of numbers involved form an AP?
If true then enter $1$ and if false then enter $0$The fee charged from a student every month by a school for the whole session, when the monthly fee is Rs 400.
If true then enter $1$ and if false then enter $0$

Answer 1

The fee charged from the student in $1^{st}$ month $=400$

The fee charged from the student in $1^{st}$two months $=400+400=800$

Similarly The fee charged from the student in $1^{st}$ three months $=400+400+400=1200$
and so on..

Clearly it form an AP $400,800,\mathrm{1200...}$ with first term $400$ and common difference $400$.