(Q16).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.

Given: Bricks needed for the bottom step = 100.

Each successive step needs 2 bricks less than the previous step.

∴ Second step from the bottom needs = 100 – = bricks

Third step from the bottom needs = – = bricks.

Fourth step from the bottom needs = – = bricks.

Here the numbers are , , , , ….

Clearly this is an A.P. but not G.P.