Question 7

100 cm 200 cm 140 cm ? cm 8 kg 10 kg 10 kg 10 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 + 200) * 8 + 200 * 10 = 140 * 10 + (140 + ?) * 10.
==> 4400 = 1400 + (140 + ?) * 10.
==> 4400 - 1400 = (140 + ?) * 10.
==> 3000 = (140 + ?) * 10.
==> 3000 / 10 = (140 + ?).
==> (140 + ?) = 300.
==> ? = 300 - 140.
==> ? = 160
100 cm A B C D 200 cm 140 cm 160 cm 8 kg 10 kg 10 kg 10 kg Weight 1 Weight 2 Weight 3 Weight 4

Question statistics

Overview
Question ID: o8FqXYSf
Main category: Numerical Reasoning
Sub category: Weight Scales
Difficulty Level: NoneWhat is item difficulty?
Nr of times answered: 175
Average IQ of people who answered this question: 124.98
Percentage of answers correct: 34.86%
Item Response Theory (IRT)What is Item Response Theory?
Item difficulty: None / 20What is item difficulty?
Discrimination: 1.25 What is item discrimination?
Point of Maximum Information: 151.91 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 175 individual test takers who have answered this question.
Distractor AnalysisWhat is distractor analysis?
Average IQ of people who gave the correct answer: 128.73 Why does the average IQ of people who answer the questions differ per question?
Average IQ of people who gave an incorrect answer: 122.86
Percentage per answer
The graph illustrates the percentage of individual test takers, 175 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.
Response Time AnalysisWhat is response time analysis?
Optimal time to spend on question: 33 seconds What is the optimal response time?
Optimal time to spend on question
The graph illustrates the last 250 correct and incorrect answers to this question, as well as the time it took for test takers to arrive at the answer. Using this data, an average optimal time for answering the question is calculated. However, it should be noted that the optimal time may vary for individual test takers.

Time spent: you used seconds to answer this question