Chapter 4: Problem 13
If \(p\) and \(q\) are two positive integers and \(p / q=1.15\), then \(p\) can equal which one of the following? (A) 15 (B) 18 (C) 20 (D) 22 (E) 23
Short Answer
Expert verified
By checking options, \( p \) can be 23.
Step by step solution
01
Rewriting the Equation
Given that \( p/q = 1.15 \), we can rewrite this equation as \( p = 1.15q \). Thus, \( p \) is 1.15 times \( q \).
02
Checking Integer Solutions
Since both \( p \) and \( q \) are integers, \( 1.15q \) must also be an integer. Because 1.15 can be expressed as the fraction \( \frac{115}{100} \) or \( \frac{23}{20} \), we have \( p = \frac{23}{20}q \). This implies that \( q \) must be a multiple of 20 for \( p \) to be an integer.
03
Substituting Values
We need to check the given options to see which one can be written as \( \frac{23}{20}q \), where \( q \) is an integer. Since \( p = 23 \) means \( 23 = \frac{23}{20}q \), solving gives \( q = 20 \), which is an integer.
04
Verification
Verify if \( p = 23 \) satisfies the original equation. Using \( q = 20 \), we have \( \frac{23}{20} = 1.15 \), confirming \( p = 23 \) is indeed a solution that satisfies \( p/q = 1.15 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding Integer Solutions
An integer solution means the result of a calculation must be a whole number, with no fractions or decimals involved. In our exercise, both \( p \) and \( q \) are specified as integers. Thus, when we compute \( p \) from \( p = 1.15q \), the end result, \( p \), has to remain an integer.
To make \( 1.15q \) an integer, \( q \) must be a number that, when multiplied by 1.15, gives a whole number. This idea is critical since any fractional result for \( p \) would not satisfy the given condition in the problem.
In this context, rewriting 1.15 as \( \frac{23}{20} \) helps us understand that \( q \) needs to be a multiple of 20, ensuring \( \frac{23}{20}q \) results in an integer.
To make \( 1.15q \) an integer, \( q \) must be a number that, when multiplied by 1.15, gives a whole number. This idea is critical since any fractional result for \( p \) would not satisfy the given condition in the problem.
In this context, rewriting 1.15 as \( \frac{23}{20} \) helps us understand that \( q \) needs to be a multiple of 20, ensuring \( \frac{23}{20}q \) results in an integer.
- This simplifies the understanding of how integer constraints affect our solution.
- It ensures we look for values of \( q \) such that \( p \) remains a whole number.
Fractions and Ratios
Fractions and ratios are key to understanding the relationship between two numbers. In the problem, we convert the decimal 1.15 into a fraction for easier manipulation, \( \frac{23}{20} \). This fraction indicates how \( p \) relates to \( q \).
Fractions, like \( \frac{23}{20} \), show us how one quantity is multiplied to obtain another. Here, \( 23 \) is the numerator and \( 20 \) is the denominator, indicating that \( p \) is 23 parts of 20 parts of \( q \).
Fractions, like \( \frac{23}{20} \), show us how one quantity is multiplied to obtain another. Here, \( 23 \) is the numerator and \( 20 \) is the denominator, indicating that \( p \) is 23 parts of 20 parts of \( q \).
- This transformation of the decimal helps us apply the concept of ratios, showing a clear multiplicative relationship.
- Understanding how decimals convert to fractions assists in precise calculations and ensures integer results, aligning with the integer condition in the problem.
Problem Solving Steps
Breaking down a problem into manageable steps is crucial for finding the right solution. In this problem, we use a structured approach:
**Step 1: Rewriting the Equation**
Start by expressing the given decimal, 1.15, as a fraction. This sets the foundation for further calculations and understanding the nature of \( p \) and \( q \).
**Step 2: Checking Integer Solutions**
Once expressed as \( p = \frac{23}{20}q \), we focus on finding values of \( q \) that keep \( p \) as an integer. Discovering that \( q \) must be a multiple of 20 is vital.
**Step 3: Substituting Values**
Testing the given options, we solve to find which values match \( \frac{23}{20}q \). This helps us identify the potential solution that satisfies the integer condition.
By verifying option \( E \), \( p = 23 \), we ensure it conforms to all derived equations. This systematic method guarantees accurate and logical solution finding, crucial for problems involving integer constraints and ratios.
**Step 1: Rewriting the Equation**
Start by expressing the given decimal, 1.15, as a fraction. This sets the foundation for further calculations and understanding the nature of \( p \) and \( q \).
**Step 2: Checking Integer Solutions**
Once expressed as \( p = \frac{23}{20}q \), we focus on finding values of \( q \) that keep \( p \) as an integer. Discovering that \( q \) must be a multiple of 20 is vital.
**Step 3: Substituting Values**
Testing the given options, we solve to find which values match \( \frac{23}{20}q \). This helps us identify the potential solution that satisfies the integer condition.
By verifying option \( E \), \( p = 23 \), we ensure it conforms to all derived equations. This systematic method guarantees accurate and logical solution finding, crucial for problems involving integer constraints and ratios.