4 is 25% of what numbe

My first guess is 100. If that fails, my second guess is 20.

To solve this, you would set it up like so:

is/of = X/100, X being the percentage you are trying to find.

then you would substitute what you know:

4/25 = X/100

then cross multiply to get rid of the fraction:

4 x 100 = 400

25 x X = 25X

then set it equal:

400 = 25X

then divide both sides by 25

25X/25 = X

400/25 = 16

then you have X = 16