Persevere with Problems Decide whether the following statement is
1 answer:
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Answer:
The mean score for all students on the quiz was 86.
Step-by-step explanation:
This question is solved by a weighed average.
To find the weighed average, we add the values multiplied by their weight, and after that we divide by the sum of weights.
In this problem, we have that:
Mr. Spears had 20 students in his class with a mean score of 80.
So 80 has a weight of 20.
Mrs. Guyton's class of 30 students had a mean score of 90.
So 90 has a weight of 30.
Overall, what was the mean score for all students on the quiz
The mean score for all students on the quiz was 86.
Set up the following equations:
x represents car A's speed, and y represents car B's speed.
We'll use elimination to solve this system of equations. Multiply the first equation by 7:
Combine both equations:
Divide both sides by 28 to get x by itself:
The speed of car A is 80 mph.
Since we now know the value of one of the variables, we can plug it into the first equation:
Subtract 160 from both sides.
Divide both sides by 2 to get y by itself:
The speed of car B is 60 mph.
x represents car A's speed, and y represents car B's speed.
We'll use elimination to solve this system of equations. Multiply the first equation by 7:
Combine both equations:
Divide both sides by 28 to get x by itself:
The speed of car A is 80 mph.
Since we now know the value of one of the variables, we can plug it into the first equation:
Subtract 160 from both sides.
Divide both sides by 2 to get y by itself:
The speed of car B is 60 mph.