To solve each of the problems:
(a) To find out what number 15% of it is equal to 12, you can set up the equation:
\[ 0.15 \times x = 12 \]
To find \( x \), divide both sides by 0.15:
\[ x = \frac{12}{0.15} \]
Calculating that gives:
\[ x = 80 \]
So, 15% of 80 is 12.
(b) To find out what percent 40 of 12 is, you first need to calculate what fraction 40 is of 12 and then convert it to a percentage.
First, calculate the fraction:
\[ \frac{40}{12} \]
Now, simplify:
\[ \frac{40}{12} = \frac{10}{3} \approx 3.33 \]
To convert this fraction to a percentage, multiply by 100:
\[ \frac{10}{3} \times 100 \approx 333.33% \]
Therefore, 40 is approximately 333.33% of 12.