Answer:
86%
Step-by-step explanation:
Let g represent the mean mark for the 10 girls in the class. Then the mean mark for the class was ...
10g +20(62%) = 30(70%)
g = 3(.7) -2(.62) . . . . . . . . . divide by 10 and subtract 2(.62)
g = .86 = 86%
The mean mark for girls was 86%.
_____
You can do this in your head if you consider it in terms of deviations from the mean. The second equation above can be rewritten and factored as ...
g = 70% +2(70% -62%)
That is, because there are 2 boys for every girl, the girl's score is above the mean by an amount that is 2 times the amount that the boy's score is below the mean. The boys' score is below by 8%, so the girls' score is above by 16%, so is 86%.
Answer: 500m
Explanation:
If the scale of the drawing is 1:500 then the real playground should be 500:1 which is 500m
Answer:
x=6
Step-by-step explanation:
Group Like Terms:
3x+x+30=10+2x+5x+2
Add similar elements 3x+x=4x:
4x+30=10+2x+5x+2
Add similar elements 2x+5x=7x:
4x+30=10+7x+2
Group like terms:
4x+30=7x+10+2
Add the numbers 10+2=12:
4x+30=7x+12
Subtract 30 from both sides:
4x+30-30=7x+12-30
Simplify:
4x=7x-18
Subtract 7x from both sides:
4x-7x=7x-18-7x
Simplify:
-3x=-18
Divide both sides by -3:
Simplify:
x=6
Hence, the correct answer is 6
Answer:
rational, irrational is like pi or \sqrt{-7}
Step-by-step explanation:
You need to foil, The answer is D
