Incorrectly 8075

Katka solved an example from mathematics. She could calculate 50% of the examples, guess the remaining questions, and guess one-fifth of them. She had 12 answers incorrectly. How many tasks did the test contain?

Correct answer:

n =  30

Step-by-step explanation:


12 = 0.50n ·(1-1/5)

12 = 0.50·n ·(1-1/5)

2n = 60


n = 60/2 = 30

n = 30

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