GMAT: Data sufficiency 35 | Data sufficiency | GMAT | Khan Academy

TL;DR

Problems involving credit card balances and exponents are analyzed and solved using algebraic equations.

Transcript

We're on problem 141. On Jane's credit card account, the average daily balance for a 30 day billing cycle-- when I see these long paragraphs it starts to give you a headache-- the average daily balance for a 30 day billing cycle is the average of the daily balances at the end of each of the 30 days. OK, so they take the average balance of each of t... Read More

Key Insights

• 💳 Calculating the average daily balance for a credit card account requires considering the daily balances and their respective days in a billing cycle.
• ❓ Algebraic techniques, such as simplifying equations and solving linear equations, can be used to analyze and solve problems involving exponents.
• 💁 Certain statements in problem-solving can provide valuable information to simplify and solve equations.

Questions & Answers

Q: How is the average daily balance on Jane's credit card account calculated for a 30-day billing cycle?

The average daily balance is the sum of the product of the daily balances and their respective days divided by the total number of days in the billing cycle. In this case, it is calculated using the formula: ($600 x days with $600 balance + $300 x days with $300 balance) / 30.

Q: How does Statement 1 in the second problem help in solving the equation involving exponents?

Statement 1 provides information about the payment cycle on the 21st day of the billing cycle. This allows us to determine that Jane's balance was $600 for 20 days and $300 for 10 days, which can be used to calculate the average daily balance.

Q: How does Statement 2 in the second problem contribute to solving the equation?

Statement 2 states that x is greater than 0 and is equal to b. This allows us to simplify the equation and conclude that it is only true if x equals 0. However, since x is greater than 0 according to the statement, the equation is not true.

Summary & Key Takeaways

• The first problem involves calculating the average daily balance on Jane's credit card account for a 30-day billing cycle, given her initial balance and a payment made during the cycle.

• The second problem asks if a certain equation involving exponents is equal to a specific value. The equation is simplified and analyzed using algebraic techniques.