Question

15 is 5% of what number?
18 is 40% of what number?
24 is 80% of what number?
54 is 75% of what number?
12 is 48% of what number?
36 is 9% of what number?
6 is 3.2% of what number?
5 is 0.4% of what number?
42 is 120% of what number?
108 is 180% of what number?

Explanation:

Let's solve each problem one by one using the formula: If \( a \) is \( p\% \) of \( x \), then \( x=\frac{a}{\frac{p}{100}}=\frac{100a}{p} \)

1. 15 is 5% of what number?

Step1: Identify \( a = 15 \), \( p = 5 \)

Step2: Apply the formula \( x=\frac{100\times15}{5} \)

\( x=\frac{1500}{5}=300 \)

2. 18 is 40% of what number?

Step1: Identify \( a = 18 \), \( p = 40 \)

Step2: Apply the formula \( x=\frac{100\times18}{40} \)

\( x=\frac{1800}{40} = 45\)

3. 24 is 80% of what number?

Step1: Identify \( a = 24 \), \( p = 80 \)

Step2: Apply the formula \( x=\frac{100\times24}{80} \)

\( x=\frac{2400}{80}=30 \)

4. 54 is 75% of what number?

Step1: Identify \( a = 54 \), \( p = 75 \)

Step2: Apply the formula \( x=\frac{100\times54}{75} \)

\( x=\frac{5400}{75} = 72\)

5. 12 is 48% of what number?

Step1: Identify \( a = 12 \), \( p = 48 \)

Step2: Apply the formula \( x=\frac{100\times12}{48} \)

\( x=\frac{1200}{48}=25 \)

6. 36 is 9% of what number?

Step1: Identify \( a = 36 \), \( p = 9 \)

Step2: Apply the formula \( x=\frac{100\times36}{9} \)

\( x=\frac{3600}{9}=400 \)

7. 6 is 3.2% of what number?

Step1: Identify \( a = 6 \), \( p = 3.2 \)

Step2: Apply the formula \( x=\frac{100\times6}{3.2} \)

\( x=\frac{600}{3.2}=187.5 \)

8. 5 is 0.4% of what number?

Step1: Identify \( a = 5 \), \( p = 0.4 \)

Step2: Apply the formula \( x=\frac{100\times5}{0.4} \)

\( x=\frac{500}{0.4}=1250 \)

9. 42 is 120% of what number?

Step1: Identify \( a = 42 \), \( p = 120 \)

Step2: Apply the formula \( x=\frac{100\times42}{120} \)

\( x=\frac{4200}{120}=35 \)

10. 108 is 180% of what number?

Step1: Identify \( a = 108 \), \( p = 180 \)

Step2: Apply the formula \( x=\frac{100\times108}{180} \)

\( x=\frac{10800}{180}=60 \)

Answer:

s:

1. \( 300 \)
2. \( 45 \)
3. \( 30 \)
4. \( 72 \)
5. \( 25 \)
6. \( 400 \)
7. \( 187.5 \)
8. \( 1250 \)
9. \( 35 \)
10. \( 60 \)