Number theory · Divisibility rules · Digit sums · Decimal representation · Casework counting
A kangaroo called Pythagoras likes exactly those natural numbers that are divisible by \(4\), have digit sum \(3\), and have exactly five digits equal to \(0\) in their decimal representation. How many natural numbers does the kangaroo Pythagoras like?
- A \(15\)
- B \(16\)
- C \(19\)
- D \(20\)
- E \(25\)
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Slovenian High School Mathematics Competition for Vega Awards (MaSSA), drzavno (national) round 2017, 1. letnik, category A, problem A3. Organized by DMFA Slovenije (Society of Mathematicians, Physicists and Astronomers of Slovenia). Source