Unit 12 · Multi-Step Conditional Reasoning
Marble Token Swap — Find Alice's Roll
Lesson 15 of 30
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About this lesson
Three friends take turns rolling a dice and swapping marbles. By the end you know everyone's total — but you have to work backwards to figure out the last roll.
Chapters
0:00Introduction
0:23Question
1:08Strategy
1:43Step 1: Kai rolls 5 (odd — receives from each other player)
2:17Step 2: Joe rolls 2 (even — gives to each other player)
2:49Step 3: Read Alice's roll from the gap to the final totals
4:28Correct answer
Question
Kai, Joe and Alice have 30 marbles each.
They take it in turns to roll a dice.
- If the number rolled is even, then that player has to give the number of marbles shown on the face of the dice to each of the other two players.
- If the number rolled is odd, then that player receives the number of marbles shown on the face of the dice from each of the other two players.
Kai rolls a 5.
Joe rolls a 2.
If the friends end up with 41, 20 and 29 marbles respectively, which number does Alice roll?
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