Question

# A certain colony of bacteria began with one cell, and the population doubled every 20 minutes. What was the population of the colony after 2 hours?

- 6
- 12
- 32
- 64

Hint:

**Hint:**

We need to simply find the population of the colony after 2 hours, where the given condition is that the population doubles after every 20 minutes.

## The correct answer is: 64

### The relation between hours and minutes is given by

1 hour = 60 minutes

This can be written as

1 hour =

So, we get

2 hours = 2.

That is , 2 hours have 6 sessions of 20 minutes.

Given, the initial population is 1.

Also, the population doubles every 20 minutes.

And this happens 6 times,

So the population of the colony after 2 hours

64

Thus, the correct option is D)

**Note:**

This is a logical question and doesn’t require any prior knowledge except the idea of multiplication. This could also be solved by simply making a table with an interval of 20 min and population which is multiplies by 2 in consecutive cells till we get 2 hours.

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