Unit 3 · Measurement and Data
$10 Note — Fewest 50¢ and 10¢ Coins?
Lesson 7 of 13
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About this lesson
Change puzzles with coin limits reward a fixed order: total cost → change → use big coins first to minimise how many coins you receive.
Chapters
0:00Introduction
0:20The Question
1:00Calculating the Total Cost
1:24Calculating the Total Change Owed
1:48Minimising the Coin Count Under Constraints
2:29Exam Strategy — The Greedy Optimization Axiom
3:05Confirming the Final Option
Question
Oliver buys 2 chocolates at $1.50 each and 4 apples at $0.70 each.
He pays with a $10 note.
The cashier has only 50-cent and 10-cent coins (no other coins).
What is the fewest number of coins Oliver can receive as change?
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