Half the people on a bus get off at each stop after the first and no one gets on after the first stop. If only one person gets off at stop number 7, how many people got on at the first stop?

Question: Half the people on a bus get off at each stop after the first and no one gets on after the first stop. If only one person gets off at stop number 7, how many people got on at the first stop?

Solution:
Given,
After the first stop, half the people on the bus get off at each stop.

At stop number 7, only 1 person gets off.
Since half of the people get off at that stop,
people on the bus before stop 7 = 1 × 2 = 2

Now we go backward:

Before stop 7 = 2 people
Before stop 6 = 2 × 2 = 4 people
Before stop 5 = 4 × 2 = 8 people
Before stop 4 = 8 × 2 = 16 people
Before stop 3 = 16 × 2 = 32 people
Before stop 2 = 32 × 2 = 64 people

So, 64 people got on at the first stop.

Correct Answer: খ) 64