Guess my number : Your friend chooses an integer between 0 and 100. Y

1.	Guess my number : Your friend chooses an integer between 0 and 100. You have to find out that number by asking questions, but your friend can only answer ‘Yes’ or ‘No’. What strategy would you use ?
Answer» Let my friend choosen 73; then my questions may be like this. Q : Does it lie in the first 50 numbers ? A: No . Q : Does it lie between 50 and 60 ? A: No Q : Does it lie between 60 and 70 ? A: No Q : Does it lie between 70 and 80 ? A: Yes [then my guess would be “it is a number from 70 to 80] Q : Is it an even number ? A: No [my guess : it should be one of the numbers 71, 73, 75, 77 and 79] Q : Is it a prime number ? A: Yes [my guess : it may be 71, 73 or 79] Q : Is it less than 75 ? A: Yes [my guess : it may be either 71 or 73] Q : Is it less than 72 ? A: No Then the number is 73. Therefore the strategy is → Use number properties such as even, odd, composite or prime to determine the number.

Guess my number : Your friend chooses an integer between 0 and 100. You have to find out that number by asking questions, but your friend can only answer ‘Yes’ or ‘No’. What strategy would you use ?

Answer»

Let my friend choosen 73; then my questions may be like this.

Q : Does it lie in the first 50 numbers ?

A: No .

Q : Does it lie between 50 and 60 ?

A: No

Q : Does it lie between 60 and 70 ?

A: No

Q : Does it lie between 70 and 80 ?

A: Yes

[then my guess would be “it is a number from 70 to 80]

Q : Is it an even number ?

A: No

[my guess : it should be one of the numbers 71, 73, 75, 77 and 79]

Q : Is it a prime number ?

A: Yes

[my guess : it may be 71, 73 or 79]

Q : Is it less than 75 ?

A: Yes

[my guess : it may be either 71 or 73]

Q : Is it less than 72 ?

A: No

Then the number is 73.

Therefore the strategy is → Use number properties such as even, odd, composite or prime to determine the number.