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:
47
Step-by-step explanation:
^
Answer: 101000
Step-by-step explanation: It would be rounded to 101000 because the nearest 100 would be a 1000.
Answer:
0.3[x-2y] + 0.5x - y
Use the distributive property: a(b-c) = ab - ac
0.3x - 0.6y + 0.5x - y
Now, add/subtract all like terms
0.3x + 0.5x - 0.6y - y
0.8x - 1.6y
If you want, we can simplify that down further to:
0.8(x - 2y)
The answer:
8 times
Explanation:
If you divide 168 by 20, you get 8.4, and the whole number is 8 so that’s the answer.
