Hogwarts Express Problem Solving Set

Algebraic Equations

9. After winning the match, Professor McGonagall rewards her house with 100 chocolate frogs. Each chocolate frog comes with a wizard card. How many cards contain Professor McGonagall's picture?

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Notes:

Solution:

Let x represent the number of Professor McGonagall cards

x +5 represents the number of Professor Dumbledor cards

(1/5) x 100 = 20, the number of Professor Quirrel cards

(1/6)x represent the number of Harry Potter cards

2 x (1/6)x represents the number of Hagrid cards

100 = x + (x + 5) + 20 + (1/6)x + (2/6)x

X = 30

There are 30 Professor McGonagall cards.