Holly is thinking of a number.
$\frac{3}{4}$ of Holly's number is 39.
Work out the number Holly is thinking of.
Answer (2)
Represent Holly's number with a variable: x .
Express the given information as an equation: 4 3 x = 39 .
Solve for x by multiplying both sides by 3 4 : x = 39 × 3 4 .
Calculate the value of x : x = 52 . Therefore, the number Holly is thinking of is 52 .
Explanation
Setting up the equation Let's call the number Holly is thinking of 'x'. The problem tells us that 4 3 of this number is 39. We can write this as an equation:
The equation 4 3 x = 39
Isolating x To find the value of x, we need to isolate it. We can do this by multiplying both sides of the equation by 3 4 :
Multiplying by the inverse x = 39 × 3 4
Simplifying Now, we can simplify this expression. First, divide 39 by 3:
After division x = 13 × 4
Final Calculation Finally, multiply 13 by 4 to find the value of x:
The answer x = 52
Conclusion So, the number Holly is thinking of is 52.
Examples
Imagine you're baking a cake, and the recipe calls for 4 3 of a cup of sugar, but you only want to use 39 grams of sugar. To find out how many grams are in a full cup, you would solve this same problem. This type of calculation is useful in cooking, construction, and many other fields where you need to scale quantities up or down.
Holly's number can be found by setting up the equation 4 3 x = 39 . Solving for 'x' gives us x = 52 , so the number Holly is thinking of is 52. This process includes converting the problem into an equation, isolating the variable, and performing basic arithmetic.
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