20 is the answer.
Step-by-step explanation:
Take a look at the given question,
"75% of what number is 15"
Let's substitute this "what number" as "x"
[tex]75[/tex]%[tex] \times x = 15[/tex]
[tex]→x = \frac{15}{75 \: percent} [/tex]
[tex]→x = \frac{15}{ \frac{75}{100} } [/tex]
[tex]→x = \frac{15}{0.75} [/tex]
To make the denominator as positive for making calculations more easy, we get,
[tex]x = \frac{15 \times 100}{0.75 \times 100} [/tex]
[tex]→x = \frac{1500}{75} [/tex]
Now after doing the division, we get,
[tex]x = 20[/tex]
Hence, 75% of 20 is 15.