X + 2x - 4x + 9 combine terms
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Answer:
The new mean for the exam scores is 51
Step-by-step explanation:
the mean can be calculated using the formula
mean of scores =
before the 20 points was added, the mean of the score was = 50.
Inserting this into the formula, we have:
50 =
from this, we can compute the sum total of the scores as
sum total = 50 × 20 = 1000
when the extra 20 marks is added, the sum of the entire scores will be changed to 1000 + 20 = 1020.
Hence the new mean will be computed as (New Sum total of scores / Number of students)
= = 51.
∴ The new mean of the scores is = 51
In order to solve this problem, we must solve an equation.
First, we need to define our unknown.
Let's call our number "n".
So, the sum of the number and 6 is the same as saying n+6
Then we need to multiply it by 2 (since it's twice the sum)
2(n+6)
This whole thing is equal to three times of the difference of the number and 8
n-8 is equal to the difference between the number and 8, then we need to multiply it by three.
3(n-8)
now, we set both sides equal and solve
The number is 36