Sakib Knows The Number!
Ragib: I got digits of a 2 digit number
Sakib: Is it an odd?
Ragib: Yes. Moreover, the sum of the digits of the number is a prime!
Sakib: The difference of the digits of the number is also a prime?
Ragib: Of course! Last of all, the multiply of the digits is equal to one of the digits!!
Sakib: Oh no! I know the number. It’s your roll number!
What is that number!
The digits may be 1,2,3,4,5,6,7,8,9,0.
Since two digit number, 0 can only be put in the second digit position.
But that will make the number even. So 0 is not any of the digits!!
1* any digit=1 or the digit
2*any digit(not 1) = not 2 or not the digit
3*any digit(not 1) = not 3 or not the digit
4*any digit(not 1) = not 4 or not the digit
5*any digit(not 1) = not 5 or not the digit
6*any digit(not 1) = not 6 or not the digit
7*any digit(not 1) = not 7 or not the digit
8*any digit(not 1) = not 8 or not the digit
9*any digit(not 1) = not 9 or not the digit
So its clear one digit is 1.
So the number may be 11,21,31,41,51,61,71,81,91.
But the sum of the 2 digit is also a prime!
So 31,51,71,81,91 will be ignored!
Now the answer may be 11,21,41,61
But the difference of the digit also is a prime!!
So 11,21 will be ignored!!!!
So the answer is 41/61…..
What a puzzle…!!!
numbers that follow odd and sum of digits is a prime are :11,21,23,25,29,41,43,49,61,65,67,83,85.
among these numbers follows “difference of digits also prime” are : 25,29,41,47,49,61,83,85.
last but not least , product of digits is same as one of it’s digits means one digit should be 1.
So Answer is 41 or 61.
Your Answer
More puzzles to try-
Dingy, Woman, Dogs, Rabbits and Lettuce transportation puzzle
A woman has two dogs, three rabbits and lettuce. She must cross a river. The dingy is unable to transport ...Read More »Find the Houses
A small town is visited by an ice-cream truck every day. On the first day of February, the truck visits ...Read More »Think with mind riddle
It is a surprise! It is a miracle! It sprouted without a seed, It stood without a trunk. Think it ...Read More »Sophie’s favorite plant puzzle
Sophie who is a housemaid, She knows her boundaries well. She is good at equations. Her favorite vegetable is cauliflower. ...Read More »Train, Car & Walk riddle
Every day, John takes the train to travel from his work back to Mexico City, his place of residence. Usually, ...Read More »Ages of Daughters
Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their ...Read More »How many cats do you think there were?
A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number ...Read More »How is this situation explained?
A boy and his father are caught in a traffic accident, and the father dies. Immediately the boy is rushed ...Read More »Flipping cards
You’re given a regular deck of 52 playing cards. In the pile you’re given, 13 cards face up and the ...Read More »Trivia Question
why number 8549176320 is one of a kind?Read More »How many brownies must you start with to give your friend 2 brownies?
You’re going to a friends house and want to give them some brownies. On the way to their house you ...Read More »Probability of Firing Revolver Puzzle
Henry has been caught stealing cattle and is brought into town for justice. The judge is his ex-wife Gretchen, who ...Read More »A Man in Mexico City riddle
A man in Mexico City has 20 Peso. He spends 16 Peso on flowers, and 3 Peso on lunch (hot ...Read More »Has two eyes riddle
It is flat as a leaf, round as a ring, Has two eyes, can not see a thing. What is ...Read More »Create correct mathematical expression
Replace the # symbols with mathematical operations (add, less, multiply or divide) such that the following becomes correct: 9 # ...Read More »How did the robber want to die?
A robber tried to steal the crown jewels. He got caught by the King’s guards and was taken to the ...Read More »How far can a rabbit run into the woods?
How far can a rabbit run into the woods?Read More »Light makes strange
Different colors of lights make him strange, Consequently into different sizes he gets changed. Who is he?Read More »Fast and Slow
For someone it move fast, For someone it move slow; But its speed is truly constant, And nowhere it go. ...Read More »Father & Son riddle
Two fathers and two sons sat down to take tea. They had exactly three cup of tea, each person had ...Read More »