Fill in the blanks

(1)3:4=(......)%

(2) 0.75=( .....)%

(3) 6%=.......(express in decimals)

(4) If x decreased by 40% gives 135 than x =.........

(5) (11% of x)-(7% of x)=18 = x=......

Answer

### Step-by-Step Solution

**(1) Convert the ratio 3:4 into percentage.**

To convert a ratio \( A:B \) into a percentage, we use the formula:
\[ \text{Percentage} = \left( \frac{A}{B} \right) \times 100 \]
Here, \( A = 3 \) and \( B = 4 \):
\[ \text{Percentage} = \left( \frac{3}{4} \right) \times 100 \]
Calculating this:
\[ \text{Percentage} = 0.75 \times 100 = 75\% \]

**(2) Convert 0.75 into percentage.**

To convert a decimal into a percentage, we multiply by 100:
\[ 0.75 \times 100 = 75\% \]

**(3) Express 6% in decimal form.**

To convert a percentage into a decimal, we divide by 100:
\[ 6\% = \frac{6}{100} = 0.06 \]

**(4) Find \( x \) if \( x \) decreased by 40% gives 135.**

When \( x \) is decreased by 40%, it means we are left with 60% of \( x \):
\[ 0.6x = 135 \]
To find \( x \), divide both sides by 0.6:
\[ x = \frac{135}{0.6} \]
Calculating this:
\[ x = 135 \times \frac{10}{6} = 135 \times \frac{5}{3} = 225 \]

**(5) Solve \( 11\% \) of \( x \) minus \( 7\% \) of \( x \) equals 18.**

This can be expressed as:
\[ (11\% - 7\%) \cdot x = 18 \]
This simplifies to:
\[ 4\% \cdot x = 18 \]
To find \( x \), divide both sides by \( 4\% \):
\[ x = \frac{18}{0.04} \]
Calculating this:
\[ x = 18 \times 25 = 450 \]

### Final Answers
1. \( 3:4 = 75\% \)
2. \( 0.75 = 75\% \)
3. \( 6\% = 0.06 \)
4. \( x = 225 \)
5. \( x = 450 \)