In which of the following situations, does the list of numbers involved make an arithmetic progression, and why?
(iii) The cost of digging a well, after every metre of digging, when it costs Rs. 150 for the first metre and rises by Rs. 50 for each subsequent metre.

In which of the following situations, does the list of numbers involved make an arithmetic progression, and why? (i) The taxi fare after each km when the fare si Rs. 20 for the first km and rises by Rs. 8 for each additional km.

In which of the following situations, does the list of numbers involved make an arithmetic progression, and why? (iv) The amount of money in the account every year, when Rs. 10000 is deposited at compound intrest at 8% per annum.

In which of the following situations, does the list of numbers involved make an arithmetic progression, and why? (ii) The amount of air present in a cylinder when a vacuum pump removes 1//4^(th) of the air remaining in the cylinder at a time.

In which of the following situations, does the list of numbers involved in the form a G.P.? (i) Salary of Sharmila, when her salary is Rs. 5,00,000 for the first year and expected to receive yearly increase of 10%.

In which of the following situations, does the list of numbers involved in the form a G.P.? (iii) Perimeter of the each triangle , when the mid-points of sides of an equilateral triangle whose side is 24 cm are joined to form another triangle, whose mid-point in turn are joined to form still another triangle and the process continues indefinitely.

In which of the following situations, does the list of numbers involved in the form a G.P.? (ii) Number of bricks needed to make each step, if the stair case has total 30 steps. Bottom step needs 100 bricks and each successive step needs 2 bricks less than the previous step.

Think how each of the list given above form an A.P. Discuss with your friends. (e) Total savings (in Rs.) after every month for 10 month when Rs. 50 are saved each month are 50, 100, 150, 200, 250, 300, 350, 400,450,500.