Question 163 of 480
Simplify 1 - (7/3 x 5/4) + 3/5
- A. -16/15
- B. -79/60
- C. -37/15
- D. -151/60
Correct Answer:
B
Explanation
To simplify the expression \( 1 - \left( \frac{7}{3} \times \frac{5}{4} \right) + \frac{3}{5} \), we will follow a step-by-step approach.
### Step 1: Calculate the product \( \frac{7}{3} \times \frac{5}{4} \)
To multiply two fractions, we multiply the numerators together and the denominators together:
\[
\frac{7}{3} \times \frac{5}{4} = \frac{7 \times 5}{3 \times 4} = \frac{35}{12}
\]
### Step 2: Substitute back into the expression
Now we substitute \( \frac{35}{12} \) back into the original expression:
\[
1 - \frac{35}{12} + \frac{3}{5}
\]
### Step 3: Convert \( 1 \) to a fraction with a common denominator
To perform the operations, we need a common denominator. The denominators we have are \( 12 \) and \( 5 \). The least common multiple (LCM) of \( 12 \) and \( 5 \) is \( 60 \).
Now, we convert each term to have a denominator of \( 60 \):
- For \( 1 \):
\[
1 = \frac{60}{60}
\]
- For \( \frac{35}{12} \):
\[
\frac{35}{12} = \frac{35 \times 5}{12 \times 5} = \frac{175}{60}
\]
- For \( \frac{3}{5} \):
\[
\frac{3}{5} = \frac{3 \times 12}{5 \times 12} = \frac{36}{60}
\]
### Step 4: Rewrite the expression with a common denominator
Now we can rewrite the expression:
\[
\frac{60}{60} - \frac{175}{60} + \frac{36}{60}
\]
### Step 5: Combine the fractions
Now we can combine the fractions:
\[
\frac{60 - 175 + 36}{60} = \frac{60 + 36 - 175}{60} = \frac{96 - 175}{60} = \frac{-79}{60}
\]
### Final Answer
Thus, the simplified expression is:
\[
\frac{-79}{60}
\]
### Conclusion
The correct option is **B. -79/60**.
### Explanation of Other Options
- **A. -16/15**: This option is incorrect because it does not match the calculated result. The value of \(-16/15\) is approximately \(-1.0667\), which is not equivalent to \(-79/60\) (approximately \(-1.3167\)).
- **C. -37/15**: This option is also incorrect. The value of \(-37/15\) is approximately \(-2.4667\), which is far from our result of \(-79/60\).
- **D. -151/60**: This option is incorrect as well. The value of \(-151/60\) is approximately \(-2.5167\), which does not match our result.
### Revision Summary
- To simplify expressions involving fractions, always find a common denominator.
- Multiply fractions by multiplying numerators and denominators.
- Convert whole numbers to fractions with the same denominator for easy addition/subtraction.
- Carefully combine fractions and simplify to find the final answer.