Sunday Afternoon Maths VII
Posted on 2014-04-06
Reverse bases
Find two digits \(a\) and \(b\) such that \(ab\) in base 10 is equal to \(ba\) in base 4.
Find two digits \(c\) and \(d\) such that \(cd\) in base 10 is equal to \(dc\) in base 7.
Find two digits \(e\) and \(f\) such that \(ef\) in base 9 is equal to \(fe\) in base 5.
Ninety nine
Source: UKMT Senior Maths Challenge 2013
In a 'ninety nine' shop, all items cost a number of pounds and 99 pence. Susanna spent £65.76. How many items did she buy?
If you enjoyed these puzzles, check out Advent calendar 2025,
puzzles about complex numbers, or a random puzzle.
puzzles about complex numbers, or a random puzzle.