Keep in mind the the word "percent" translates to "for each 100." 25% can be read as "25 for each 100," which has the fractional representation [tex] \frac{25}{100} [/tex] and the decimal representation 0.25. All of these representations are just different ways of writing the same value.
Note too that the fraction [tex] \frac{25}{100} [/tex] can be reduced to [tex] \frac{1}{4} [/tex], so what the question is really asking is: 1/4 of what number is 9?
Well, if we know that 1/4 of the number is 9, we can easily find how large the whole number is by finding all 4/4 of it (the whole number), or 4 x 9, which multiplies out to 36.
