Answer:
3
Step-by-step explanation:
If 6 numbers have a mean value of 10, it means that the sum of the numbers divided 6 is equal to 10. This can be expressed as:
x÷6=10
x=60
The new number added will be the 7th number and now the mean is 9. You have to ask what number divided by 7 is equal to 9? This can be expressed as:
y÷7=9
y=63
63-60=3
So the new number added is 3
Answer:
Step-by-step explanation:
3x+7y-2x+3y+7
group like terms
3x-2x +7y+3y +7
x+10y+7
Answer:
y-9= -3(x+2)
Step-by-step explanation:
y-y1= "M" (x-x1)
y1= 9
X1= -2
Answer:
y=2/3+11
Step-by-step explanation:
Answer:
The twins would be 13 years old.
Step-by-step explanation:
21+21+21+13+13 = 89