Find a common denominator for the fractions inside the brackets: 7 6 โ + 8 3 โ โ 2 1 โ = 56 48 โ + 56 21 โ โ 56 28 โ .
Add and subtract the fractions: 56 48 + 21 โ 28 โ = 56 41 โ .
Multiply the result by 3 4 โ : 56 41 โ ร 3 4 โ = 168 164 โ .
Simplify the fraction: 168 164 โ = 42 41 โ . The final answer is 42 41 โ โ .
Explanation
Understanding the Problem We are asked to evaluate the expression [ 7 6 โ + 8 3 โ โ 2 1 โ ] 3 4 โ . This involves adding and subtracting fractions within the brackets, and then multiplying the result by another fraction.
Finding a Common Denominator First, we need to find a common denominator for the fractions inside the brackets: 7 6 โ , 8 3 โ , and 2 1 โ . The least common multiple of 7, 8, and 2 is 56. So we rewrite each fraction with a denominator of 56:
7 6 โ = 7 ร 8 6 ร 8 โ = 56 48 โ
8 3 โ = 8 ร 7 3 ร 7 โ = 56 21 โ 2 1 โ = 2 ร 28 1 ร 28 โ = 56 28 โ
Adding and Subtracting Fractions Now we can add and subtract the fractions inside the brackets:
56 48 โ + 56 21 โ โ 56 28 โ = 56 48 + 21 โ 28 โ = 56 69 โ 28 โ = 56 41 โ
Multiplying by 4/3 Next, we multiply the result by 3 4 โ :
56 41 โ ร 3 4 โ = 56 ร 3 41 ร 4 โ = 168 164 โ
Simplifying the Fraction Finally, we simplify the fraction by dividing both the numerator and the denominator by their greatest common divisor, which is 4:
168 164 โ = 168 รท 4 164 รท 4 โ = 42 41 โ
Final Answer Therefore, the value of the expression is 42 41 โ .
Examples
Fractions are used in everyday life, such as when cooking, baking, or measuring ingredients. For example, if a recipe calls for 4 3 โ cup of flour and you only want to make half the recipe, you need to calculate 2 1 โ ร 4 3 โ = 8 3 โ cup of flour. Understanding how to add, subtract, multiply, and simplify fractions is essential for accurate measurements and successful cooking.
To solve [ 7 6 โ + 8 3 โ โ 2 1 โ ] โ
3 4 โ , we find a common denominator, calculate the combined fractions to get 56 41 โ , and then multiply by 3 4 โ to result in 42 41 โ .
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