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:20 ^v^ Please follow me
Step-by-step explanation:
200/40=5
5+15=20
Answer:
Here is the answer with the steps
Step-by-step explanation:
Hope you liked it!!
Use Pythagoras theorem. (a^2 + b^2 = c^2)
300^2+300^2 = 180000
√180000 = 424.3
The answer is 424 foot.
Hope this helps.
