Question 224 of 480
Evaluate \(\frac{\frac{1}{10}\times\frac{2}{3}+\frac{1}{4}}{\frac{\frac{1}{2}}{\frac{3}{5}}-\frac{1}{4}}\)
- A. \(\frac{7}{12}\)
- B. \(\frac{19}{35}\)
- C. \(\frac{2}{25}\)
- D. \(\frac{19}{60}\)
Correct Answer:
B
Explanation
To evaluate the expression
\[
\frac{\frac{1}{10}\times\frac{2}{3}+\frac{1}{4}}{\frac{\frac{1}{2}}{\frac{3}{5}}-\frac{1}{4}},
\]
we will break it down step-by-step.
### Step 1: Evaluate the Numerator
The numerator is
\[
\frac{1}{10} \times \frac{2}{3} + \frac{1}{4}.
\]
**Calculating \(\frac{1}{10} \times \frac{2}{3}\):**
\[
\frac{1}{10} \times \frac{2}{3} = \frac{1 \times 2}{10 \times 3} = \frac{2}{30} = \frac{1}{15}.
\]
**Now, add \(\frac{1}{15}\) and \(\frac{1}{4}\):**
To add these fractions, we need a common denominator. The least common multiple (LCM) of 15 and 4 is 60.
**Convert \(\frac{1}{15}\) to a fraction with a denominator of 60:**
\[
\frac{1}{15} = \frac{1 \times 4}{15 \times 4} = \frac{4}{60}.
\]
**Convert \(\frac{1}{4}\) to a fraction with a denominator of 60:**
\[
\frac{1}{4} = \frac{1 \times 15}{4 \times 15} = \frac{15}{60}.
\]
**Now, add the two fractions:**
\[
\frac{4}{60} + \frac{15}{60} = \frac{4 + 15}{60} = \frac{19}{60}.
\]
### Step 2: Evaluate the Denominator
The denominator is
\[
\frac{\frac{1}{2}}{\frac{3}{5}} - \frac{1}{4}.
\]
**Calculating \(\frac{\frac{1}{2}}{\frac{3}{5}}\):**
Dividing by a fraction is the same as multiplying by its reciprocal:
\[
\frac{1}{2} \div \frac{3}{5} = \frac{1}{2} \times \frac{5}{3} = \frac{1 \times 5}{2 \times 3} = \frac{5}{6}.
\]
**Now, subtract \(\frac{1}{4}\) from \(\frac{5}{6}\):**
Again, we need a common denominator. The LCM of 6 and 4 is 12.
**Convert \(\frac{5}{6}\) to a fraction with a denominator of 12:**
\[
\frac{5}{6} = \frac{5 \times 2}{6 \times 2} = \frac{10}{12}.
\]
**Convert \(\frac{1}{4}\) to a fraction with a denominator of 12:**
\[
\frac{1}{4} = \frac{1 \times 3}{4 \times 3} = \frac{3}{12}.
\]
**Now, subtract the two fractions:**
\[
\frac{10}{12} - \frac{3}{12} = \frac{10 - 3}{12} = \frac{7}{12}.
\]
### Step 3: Combine the Results
Now we have:
- Numerator: \(\frac{19}{60}\)
- Denominator: \(\frac{7}{12}\)
We need to evaluate:
\[
\frac{\frac{19}{60}}{\frac{7}{12}}.
\]
**Dividing by a fraction:**
This is the same as multiplying by the reciprocal:
\[
\frac{19}{60} \div \frac{7}{12} = \frac{19}{60} \times \frac{12}{7} = \frac{19 \times 12}{60 \times 7}.
\]
**Calculating the numerator and denominator:**
\[
19 \times 12 = 228,
\]
\[
60 \times 7 = 420.
\]
So we have:
\[
\frac{228}{420}.
\]
### Step 4: Simplify the Fraction
To simplify \(\frac{228}{420}\), we need to find the greatest common divisor (GCD) of 228 and 420.
**Finding the GCD:**
- The prime factorization of 228 is \(2^2 \times 3 \times 19\).
- The prime factorization of 420 is \(2^2 \times 3 \times 5 \times 7\).
The GCD is \(2^2 \times 3 = 12\).
**Now divide both the numerator and denominator by 12:**
\[
\frac{228 \div 12}{420 \div 12} = \frac{19}{35}.
\]
### Final Answer
Thus, the final answer is
\[
\frac{19}{35}.
\]
### Explanation of Options
- **Option A: \(\frac{7}{12}\)** - This is incorrect because it does not represent the final value of the expression.
- **Option B: \(\frac{19}{35}\)** - This is the correct answer as shown in our calculations.
- **Option C: \(\frac{2}{25}\)** - This is incorrect as it does not match any part of our calculations.
- **Option D: \(\frac