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2019 NSW: Maths Puzzle 4

4th puzzle by Dr Harry Wiggins (Money, money, money)

Two choices today. Solve either puzzle (a) or (b) and post your interesting comments.

(a) If in South Africa, you only get two types of coins: R19 and R20 coins. What is the least number of coins you need to pay a bill of R2019? 

(b) A billionaire is splitting his one billion rand fortune amongst 100 relatives. The first relative gets 1% of his fortune. The second relative gets 2% of the remaining fortune. Then the third relative gets 3% of the remaining fortune and so on, until the last relative gets 100% of the rest. Which relative will inherit the most money and what chunk of the original fortune will it be?

Leave your comment
2019/08/01 2:19 PM
a) (100 x R20) + (1 x R19)
= R2000 + R19
= R2019
101 coins

Erin Powers, 14
2019/08/01 2:45 PM
Well done Erin Powers!!!

Why is 101 coins the least?

Any takers for (b)???
2019/08/01 5:14 PM
b) The 10th relative gets the most R 62 815 650,96
2019/08/02 6:17 AM
Good job Japie!
2019/08/09 5:57 PM
a) 101:  100x R20 and a R19
b) 10'th relative 6,282%
2019/08/12 7:45 AM
Good job Phillip, thank you for confirming Susan and Japie's answers. You are all correct!

Can anybody proof why 14 coins in puzzle (a) is optimal?