Robin paid $120 a month on a credit card. She was late on a payment, so her monthly bill was raised to $150 a month. Which of these shows how Robin can calculate the percent increase she was charged?
A. $(150-120) / 120$
B. $150-120$
C. $150+120$
D. $(150+120) / 120
Answer (2)
Calculate the amount of increase: 150 − 120 .
Divide the amount of increase by the original amount: 120 150 − 120 .
The expression to calculate the percent increase is 120 150 − 120 .
Therefore, the answer is 120 150 − 120 .
Explanation
Problem Analysis Let's analyze the problem. Robin's credit card bill increased from $120 to $150 due to a late payment. We need to find the expression that calculates the percent increase.
Calculate the Amount of Increase To find the percent increase, we first need to calculate the amount of the increase. This is the difference between the new amount and the original amount: 150 − 120 .
Calculate the Percent Increase Next, we divide the amount of increase by the original amount to find the percent increase: 120 150 − 120 .
Final Answer Therefore, the expression that shows how Robin can calculate the percent increase she was charged is 120 150 − 120 .
Examples
Understanding percentage increases is useful in many real-life situations. For example, if you are tracking the price of groceries and the price of milk increases from $3 to $3.50, you can calculate the percentage increase to understand how much more you are paying. Similarly, if your salary increases from $50,000 to $55,000, you can calculate the percentage increase to see how much your income has grown. These calculations help you make informed decisions about budgeting, investments, and other financial matters.
To find the percent increase in Robin's credit card bill, she can use the formula 120 150 − 120 . This shows the amount of increase divided by the original amount. Therefore, the right answer is option A.
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