The image contains a set of problems involving percentages. Here’s a breakdown and solution for each of the calculations:

1. 48 is 40% of n

   • The equation: $48 = 0.40 \times n$
   • To solve for $n$, divide both sides by 0.40: $n = \frac{48}{0.40} = 120$

2. 21 is n% of 84

   • The equation: $21 = \frac{n}{100} \times 84$
   • To solve for $n$, multiply both sides by 100 and divide by 84: $n = \frac{21 \times 100}{84} = 25$

3. 18% of 27 is n

   • The equation: $n = \frac{18}{100} \times 27$
   • To find $n$, multiply 18% by 27: $n = 0.18 \times 27 = 4.86$

Summary of Solutions:

1. $n = 120$
2. $n = 25$
3. $n = 4.86$

Would you like more details or further assistance with these problems? Here are some related questions:

1. How would you solve a percentage problem when the percentage is greater than 100%?
2. What is the process to calculate percentages in real-world applications like discounts or taxes?
3. How do you convert a percentage to a decimal for calculation?
4. Can percentages be negative, and what does that mean in context?
5. How would you interpret a percentage that represents part of a whole, for example, "30% of a population"?

Tip: Always ensure that percentages are converted to decimals before performing multiplication or division.