Suppose the original quantity is 175 and the new quantity is 126. Which of these expressions represents the percent decrease?


A$\frac{175-126}{175}$
B$\frac{126-175}{126}$
C$\frac{175-126}{126}$
D$\frac{126+175}{175}$

Verified Answer :

  • The percent decrease formula is \(\frac{\text{Initial Value} - \text{Final Value}}{\text{Initial Value}} \times 100\%\).
  • Option A correctly represents this formula as \(\frac{175-126}{175}\).
  • Calculating the value: \(\frac{49}{175} = 0.28\), which is \(28\%\).
  • The final answer is \(\boxed{A, 28\%}\).

Explanation

  1. Identifying the Correct Expression

To determine the percent decrease, we identify the initial quantity as \(175\) and the new quantity as \(126\). The percent decrease measures how much a value has declined relative to its starting value, calculated using the formula:
\[ \text{Percent Decrease} = \frac{\text{Initial Value} - \text{Final Value}}{\text{Initial Value}} \times 100\% \]
Substituting our values into the formula, we have:
\[ \text{Percent Decrease} = \frac{175 - 126}{175} \times 100\% \]
Comparing this to the provided options, we see that it matches option A.

  1. Calculating the Percent Decrease

Now, we perform the arithmetic calculation to find the specific percent decrease.
First, compute the difference in the numerator:
\[ 175 - 126 = 49 \]
Next, divide this difference by the initial value:
\[ \frac{49}{175} \]
Simplifying the fraction by dividing both numerator and denominator by 7:
\[ \frac{49 \div 7}{175 \div 7} = \frac{7}{25} \]
Finally, convert this fraction to a percentage by multiplying by 100:
\[ \frac{7}{25} \times 100\% = 7 \times 4\% = 28\% \]
Thus, the percent decrease is \(28\%\).

Examples

Percent decrease is frequently used in retail to determine discounts. For example, if a jacket that originally cost \$175 is marked down to \$126, calculating the percent decrease helps customers understand the savings. By using the formula \(\frac{\text{Initial} - \text{New}}{\text{Initial}} \times 100\%\), we find the discount rate is 28%, which is useful for comparing deals across different stores.