Based on the ratio of boys/girls We can infer that the only possibility for Ellen's math class would be answer B. 14/21
Answer: high test-retest reliability
Step-by-step explanation: this is because the result of the survey was thesame with the previous result, despite the space of time between when the first survey was conducted and when the second survey was conducted. There was know observable difference in result and if conducted in the next 3 months again, it will give same result, this strongly indicate that the survey has high test-retest reliability.
Expand 8(5-r)/5=-2r as indicated: 40 - 8r
----------- = - 2r
5
Multiply both sides by 5, obtaining 40 - 8r = - 10r
Combine like terms: 40 = - 2r
Divide both sides by -2: -20 = r
The solution to 8(5-r)/5=-2r is -20. Verify this by subbing -20 for r in the given equation.
Answer:
D
Step-by-step explanation: