Step-by-step answer:
If there are 40% students that are girls , and the rest are 250 boys. Then that must mean there are 60% boys. Because that is the compliment.
i)
Because we know that 60% of the people in the group are boys, and that the amount of boys amounts to 250, we can model an equation like this.
.


There are 417 students
ii)
Because we know that the total amount is 417, we can find the amount of girls there are by multiplying the total by the percentage.

There are 167 students that are girls.
She has 24 friends.
<u><em>Explanation</em></u>
Suppose, the number of friends is 
She gave 3 pieces of gum each of her friends. So, the <u>total number of gums given to
numbers of friends</u> will be: 
She had total 77 pieces of gums and after giving to her friends, she has only 5 remaining. So, the equation will be......

So, she has total 24 friends.
They are opposites. since |-3| has the lines around it, this represents absolute value, which is not positive or negative but how far away the value is from 0. the plain -3 remains the same. |-3| is 3, because it is 3 units away from 0 on the number line.
47 1/2 oil
9 1/2 vinegar
Add the 5and 1 from the 5:1 ration to get 6. Divide 57 by 6 to get 9.5
Multiply 5 and 1 by 9.5 to get 47.5 and 9.5 as the answer