MathCastle
Counting & ProbabilityChallengeCounting Strategies: Casework, Complementary & Overcounting

Counting Strategies: Casework, Complementary & Overcounting · Challenge problem

A vending machine accepts only nickels (5 cents) and dimes (10 cents), inserted one at a time. In how many distinct orders can coins be inserted to total exactly 65 cents (so, for example, nickel-then-dime is different from dime-then-nickel)?