Question

A banker counts 128 notes in the first minute and there after he counts half the number of flotes he counted In the previous minute. How many notes he would count In five minutes?

Answer 1

In the first minute a banker counts 128 notes.

∴ a = 128

There after, in every minute he counts half the number of flotes he counted In the previous minute.

∴ r = 1/2

Total number of notes counted in five minutes = S₅

Now, S_n = \(\frac{a[1−r^n]}{1−r}\)

Putting n = 5; a = 128; r = 1/2