If you add Hillary to the friend count, that's 24. So there are 16 boys and 8 girls
So we have 2 variables here: tacos and orders of nachos.
When we translate the paragraphs into equation:

Now, in this situation we can make use the elimination method by converting 3n to -27n.

Add both equations:

So we find that one taco costs $2.75.
We can plug this into any of the first two equations to find n:

So one order of nachos cost $1.40.
The council tax bill before the increase is £1240
The equation that represents the percentage increase in council tax bill is :
percentage increase x t = £62
Where t represents the initial council tax bill - council tax bill before the 5% increase
5% x t = £62
0.05 x t = £62
Divide both sides of the equation by 0.05
t = £62 / 0.05 = £1240
To check if the answer derived is correct : 5% x 1240 = 62.
A similar question was answered here: brainly.com/question/12066598?referrer=searchResults
Write down y=f(x) and then solve the equation for x, giving something of the form x=g(y).
Find the domain of g(y), and this will be the range of f(x). ...
If you can't seem to solve for x, then try graphing the function to find the range.