Grades 5-6 Video Solutions 2021-video 2021 5-6/26

Video Transcription

Number 26. Three pirates were asked how many coins and how many diamonds their friend Greybeard had.  Each of the three answered truthfully to one question but lied answering the other. Their answers are written on the piece of paper pictured.  What is the total number of coins and diamonds that Greybeard has? So the first person said he has eight coins and six diamonds.  The second person says he has seven coins and four diamonds. And the third person said he has seven coins and seven diamonds.  Okay, so all the pirates said a different number of diamonds. Only one of them must have told the truth based on this. The other two lied.  Okay, so if two pirates lied about the diamonds, that means that two pirates told the truth about the coins.  Simply because they answered truthfully to one question but lied answering the other. So they lied about the diamonds, they told the truth about the coins.  Well, if one of those people was one and one of those people was two, that's impossible. They can't both be telling the truth and give different answers.  So the two people who are telling the truth are number two and three. They're telling the truth about the number of coins. Greybeard has seven coins.  Well, pirate one then must be the one telling the truth about the diamonds. And Greybeard must have six diamonds.  So Greybeard has seven coins plus six diamonds. That's 13 total gems. The answer is C.

Video Summary

Greybeard has 13 total gems. Two pirates told the truth about the number of coins, and one pirate told the truth regarding diamonds. Pirates two and three truthfully stated that Greybeard has seven coins, while pirate one truthfully mentioned six diamonds.