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The "Mathemagician"

A "mathemagician" makes a magic with cards. He have green, yellow, blue and red cards, numbered from 1 to 13 for each color.

He mixes the cards and says to a child: "Without I see, select a card, calculate the double of the number of this card, add 3, multiply the result by 5, and:

  • Add 1 if the card is green;

  • Add 2 if the card is yellow;

  • Add 3 if the card is blue;

  • Add 4 if the card is red.

"Tell me the end result and I will tell you the number and color of the chosen card."

Answer the following questions:

A) Johnny chooses a red card with the number 3. What is the number that Johnny should to say to the Mathemagician?

B) Marinette said "Seventy-Six" to the mathemagician. What is the number and the color of the card that she chose?

C) After choose a card, Peter says: "Sixty-one" and the mathemagician says to he: "You made a mistake". Explain how the mathemagician know that.

Note by Victor Paes Plinio
3 years ago

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