Question 7

100 cm ? cm 200 cm 140 cm 10 kg 4 kg 6 kg 6 kg
Which number should replace the question mark?

Explanation

The scale is balanced. This is the case if the distances * weights are the same on both sides of the scale: (A + B) * weigth 1 + B * weight 2 = C * weigth 3 + (C + D) * weight 4.

(100 + ?) * 10 + ? * 4 = 200 * 6 + (200 + 140) * 6.
==> (100 + ?) * 10 + ? * 4 = 3240.
==> Write without parentheses: 100 * 10 + ? * 10 + ? * 4 = 3240.
==> Simplify: ? * 14 + 1000 = 3240.
==> ? * 14 = 3240 - 1000.
==> ? = 2240 / 14.
==> ? = 160
100 cm A B C D 160 cm 200 cm 140 cm 10 kg 4 kg 6 kg 6 kg Weight 1 Weight 2 Weight 3 Weight 4

Question statistics

Overview
Question ID: MMr5dFUG
Main category: Numerical Reasoning
Sub category: Weight Scales
Difficulty Level: NoneWhat is item difficulty?
Nr of times answered: 117
Average IQ of people who answered this question: 133.74
Percentage of answers correct: 39.32%
Item Response Theory (IRT)What is Item Response Theory?
Item difficulty: None / 20What is item difficulty?
Discrimination: 3.52 What is item discrimination?
Point of Maximum Information: 138.49 What is Point of Maximum Information?
Item Characteristic Curve (ICC)
This Item Characteristic Curve shows the probability that a person with a given IQ level will correctly answer this question. This graph is based on the answers and the IQ levels of 117 individual test takers who have answered this question.
Distractor AnalysisWhat is distractor analysis?
Average IQ of people who gave the correct answer: 137.63 Why does the average IQ of people who answer the questions differ per question?
Average IQ of people who gave an incorrect answer: 130.80
Percentage per answer
The graph illustrates the percentage of individual test takers, 117 in total, who selected each answer option for this question.
Average IQ per answer
The graph displays the average IQ of test takers who chose each answer option. In an effective question, the average IQ of test takers who selected the correct answer should be significantly higher than that of test takers who selected the other options, also known as distractors.

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