# THE POWER OF 2

The power of 2 is nothing but multiplying 2 by itself.

For example, if the power of 2 is 3, we have to multiply 2 by itself 3 times.

More clearly,

23  =  2 x 2 x 2

23  =  8

## The power of 2

Powers of 2 get large very quickly. It’s true that 21 is equal to 2 and 22 equals just 4. But 213 equals 8192, which is slightly more than Earth’s diameter in miles !

Let us see, how the value of "powers of 2" gets larger and larger when we increase the powers from 0 to 10

20  =  1

21  =  2

22  =  4

23  =  8

24  =  16

25  =  32

26  =  64

27  =  128

28  =  256

29  =  512

210  =  1024

## The Power of 2 - Activity

Freelance Computer Programmer :

David is a freelance computer programmer contracted by a company that makes video games.

In his work, he often used the power of 2ⁿ to find the number of bits (or units of information) that can be arranged. The n stands for the number of bits.

In the video game of hidden treasures that he is programming, the main character wins if he collects 3 fewer hidden treasures than the highest number of bits that can be arranged in the system.

If David is working with a 16-bit system, is the main character a winner if he has collected 65,000 hidden treasures ? Explain your reasoning.

Solution :

The formula for winning number of hidden treasures is

2n - 3

Since, David is working with 16-bit system, we have to substitute 16 for 'n' in the above formula.

Then, the winning number of treasures is

216 - 3  =  65536 - 3

216 - 3  =  65533

Hence, the main character is not a winner.  Because he has only collected 65,000 hidden treasures which is less than the winning amount 65533.

## The Power of 2 - Practice Problems

Problem 1 :

A man has 5 friends. In how many ways, can he invite one or more of his friends to dinner ?

Solution :

We have '2' alternatives for each friend. That is, either he may invite or he may not invite.

Therefore, no. of all possible ways to invite  5 friends to dinner is

=  2 x 2 x 2 x 2 x 2

=  25

(But it includes the way of not inviting all the 5 friends)

So, no. of ways to invite one or more of his friends is

=  2- 1

=  32 - 1

=  31

Hence, the no. of ways to invite one more of his friends is 31.

Problem 2 :

A examination paper with 10 questions consists of 6 questions in Algebra and 4 questions in geometry. At least one question is to be attempted from each section. In  how many ways can this be done ?

Solution :

We have '2' alternatives for each question. That is, either we may attempt or we may not attempt.

Therefore,no. of ways to attempt six questions in Algebra is

=  2 x 2 x 2 x 2 x 2 x 2

=  26

(But it includes the way of not attempting all the questions)

So, no. of ways to attempt at least one question in Algebra is

=  2- 1

Similarly, no.of ways to attempt atleast one question in Geometry is

= 2- 1

Total no.ways for both the sections is

=  (2- 1)(2- 1)

=  (64 - 1)(16 - 1)

=  63 x 15

=  945

Hence, the no. of ways of attempting at least one question from each section is 945 Apart from the stuff given in this section, if you need any other stuff in math, please use our google custom search here.

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