## Question 1

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 + 180) * 6 + 180 * ? = 180 * 6 + (180 + 100) * 6.
==> 1680 + 180 * ? = 2760.
==> 180 * ? = 2760 - 1680.
==> ? = (1080 / 180.
==> ? = 6.

### Question statistics

Overview
Question ID: b4DeU2Ba
Main category: Numerical Reasoning
Sub category: Weight Scales
Difficulty Level: NoneWhat is item difficulty?
Average IQ of people who answered this question: 96.31
Item Response Theory (IRT)What is Item Response Theory?
Item difficulty: None / 20What is item difficulty?
Discrimination: 2.19 What is item discrimination?
Point of Maximum Information: 55.65 What is Point of Maximum Information?
##### Item Characteristic Curve (ICC)
Distractor AnalysisWhat is distractor analysis?
Average IQ of people who gave the correct answer: 97.42
Average IQ of people who gave an incorrect answer: 83.72
Response Time Analysis
Optimal time to spend on question: 21 seconds What is the optimal response time?
##### Optimal time to spend on question

Time spent: you used 19 seconds to answer this question