Which equation can be used to solve the problem?

180 is 40 percent of what number?
StartFraction 40 times 4.5 Over 100 times 4.5 EndFraction = StartFraction 180 Over 450 EndFraction
StartFraction 180 times 0.4 Over 100 times 0.4 EndFraction = StartFraction 72 Over 40 EndFraction
StartFraction 40 times 1 Over 180 times 1 EndFraction = StartFraction 40 Over 180 EndFraction
StartFraction 100 times 4.5 Over 40 times 4.5 EndFraction = StartFraction 450 Over 180 EndFraction

1 answer

To solve the problem "180 is 40 percent of what number?", you want to set up an equation that represents this relationship.

Let \( x \) be the unknown number. The statement can be translated into the equation:

\[ 180 = 0.4 \times x \]

From this equation, you can find \( x \) by dividing both sides by 0.4:

\[ x = \frac{180}{0.4} \]

Now let's analyze the options you provided:

  1. \( \frac{40 \times 4.5}{100 \times 4.5} = \frac{180}{450} \)
  2. \( \frac{180 \times 0.4}{100 \times 0.4} = \frac{72}{40} \)
  3. \( \frac{40 \times 1}{180 \times 1} = \frac{40}{180} \)
  4. \( \frac{100 \times 4.5}{40 \times 4.5} = \frac{450}{180} \)

The first option simplifies to \( \frac{180}{450} \) but is not directly derived from the original question. The second option can be derived from rearranging the equation but doesn't represent the percentage right. The third option is not relevant as it doesn't address the entire equation. The fourth option is also not the correct representation.

None of these directly represent the original problem using the correct equation.

However, if rearranged and simplified appropriately, you could go from \( 180 = 0.4x \) to other forms, but the simplest expression is \( \frac{180}{0.4} \) to find \( x \).

In essence, none of these options directly translate to solving for \( x \) using the original percentage equation. The best approach to find \( x \) directly from the problem should be done as mentioned earlier:

\[ x = \frac{180}{0.4} \] or equivalently understood as \( 180 = 0.4 \times x \).