"19 is 50% of what number?"
A percent is a fraction out of 100.
[tex]50%=\frac{50}{100}[/tex]
The top and bottom are both divisible by 50, so we can simplify.
[tex]\frac{50}{100}=\frac{1}2[/tex]
We can rewrite our question as "19 is half of what number?"
Of course, the reverse of halving (dividing by 2) is doubling (multiplying by 2)
[tex]19\times2=38,\ 38\div2=19[/tex]
19 is 50% of 38.
