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%.
This is so blurry, can you take another picture or type the questions out please/
Answer: $300
Step-by-step explanation:
Mr. Calvin earned 
He spent 
on food i.e.
Remaining money = 
So, he saved $300 after expenses
Answer: 5.6 cm
Step by Step: I used the same formula as the question before and I got the answer for this question. When solving questions like this, you can work backwards from the problem and then solve
Step-by-step explanation:
To get the inverse, swap the x- and y-variables, then solve for y. We should have the equation: 
Solving for y:
because 
or 
So on interchanging the variable, we get the equation:
