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%.
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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:

Step-by-step explanation:
To find the circumference of a circle, you can multiply the value of the diameter of the circle with the value of pi.


0.65 = 65% SO THE ANSWER IS 0.45 or 45%
Answer:
there are alot of things that can be rounded to 4
Answer:
Step-by-step explanation:
3a + 26 = 86
3a = 86 - 26 = 60
a = 60/3 = 20