DIY Challenge 1: The 8 bar challenge!
Share your strategy for finding the real gold bar.
What is the minimum time you need to find it?
What students worked out10
Student 7
3
Karanteacher
What’s your strategy?
Student 2
THE STRATEGY IS THAT FIRST WE WEIGH
4 TO 4
THEN
2 TO 2
THEN
1 TO 1
VOILA YOU GOT THE ANSWER
FOR 9 WE WILL DO 4 TO 4 IF THEY ARE SAME THE REMAINING BAR IS THE ANSWER IF NOT THE HEAVIER 4
THEN WE HAVE 4 THEN 2 TO 2 THEN 1 TO 1Karanteacher
That’s a good general strategy. Any way you could find the real gold bar in just 2 turns?
Student 2
FIRST WE WEIGH 3 TO 3 IF IT IS NEITHER THEN WE WEIGH 1 TO 1 IF NOT THEN WE KNOW HOW TO DO FOR 3
Student 4
3 because first we weigh 1234 and 5678. If 5678 is heavier, we weigh 56 and 78. If 78 is heavier, we weigh 7 and 8. If 7 is heavier, 7 is the real ingot
Karanteacher
What could be a better strategy?
Student 1
First we weigh 1234vs5678 which ever on is heavier e.g 1234 is heavier we measure 1vs2 we could get lucky if they are the same 1,2,5,6,7,8 are all fake now only 2 numbers remain we measure them whichever one is heavier is the real gold
Karanteacher
That’s a good strategy. I think this will take 3 turns. Do you think it’s possible using just 2 weighings?
Student 3
Minimum 2 weighing required
Put 123 on 1 side and 456 on other side.
If 123>456 then weigh 1 and 2 and decide which one is gold bar.
If 123 < 456 the we will weigh 4 and 5.
If 123 = 456 then we will 7 and 8.