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Math Kangaroo 2021 Problem 17 | Kadett

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Try this beautiful Problem based on simple Arithmetic appeared in Math Kangaroo (Kadett) 2021 Problem 17.

Math Kangaroo 2021 Problem 17 | Kadett


There are 20 questions in a quiz. Each correct answer scores 7 points, each wrong answer scores $-4$ points, and each question left blank scores 0 points. Eric took the quiz and scored 100 points. How many questions did he leave blank?

  • 0
  • 1
  • 2
  • 3
  • 4

Key Concepts


Arithmetic

Divisibility

Logic Question

Suggested Book | Source | Answer


Algebra by Gelfand

Math Kangaroo (Kadett), 2021

$1$

Try with Hints


Here given that,

Total number of questions $=20$
Score of correct answer $=7$ points
Score of wrong answer $=-4$
Eric scored $=100$ points

So that mean, the score for all of the correct answers is greater than $100$.

Now we know $7\times 16 = 112$.

Now we have to count how many wrong answers are there if the score is $100$.

Remaining question $=20-(16+3)$
So, $1$ is the correct answer.

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