You will have $5 left because if you spend 1.25 on 12 snacks you will spend $15
Consider a trapezoid GJKF with:
GH=JH (hypothesis)
FL=KL (hypothesis)
so HL is the median of trapezoid GJKF
so: HL=1/2(2.5+1.2)=1.85
The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try!