Chapter 12: Problem 63
A man gets a job with a salary of \(\$ 30,000\) a year. He is promised a \(\$ 2300\) raise each subsequent year. Find his total earnings for a 10 -year period.
Short Answer
Expert verified
The total earnings over 10 years is \( \$ 403,500 \).
Step by step solution
01
Understand the Sequence of Earnings
The man's earnings form an arithmetic sequence where the first term, \( a_1 \), is \( 30,000 \), and the common difference, \( d \), is \( 2,300 \).
02
Identify the Formula for the Total Earnings
The sum of an arithmetic sequence can be found using the formula: \[ S_n = \frac{n}{2} \times (2a_1 + (n-1) \cdot d) \] where \( n \) is the number of terms, \( a_1 \) is the first term, and \( d \) is the common difference.
03
Substitute the Known Values into the Formula
Substitute \( n = 10 \), \( a_1 = 30,000 \), and \( d = 2,300 \) into the formula: \[ S_{10} = \frac{10}{2} \times (2 \times 30,000 + (10 - 1) \times 2,300) \]
04
Calculate the Inside Components of the Formula
Calculate the components inside the parentheses: \[ 2 \times 30,000 = 60,000 \] \[ 9 \times 2,300 = 20,700 \] Thus, the inside of the parentheses becomes \( 60,000 + 20,700 = 80,700 \).
05
Solve for the Total Earnings
Now calculate \( S_{10} \): \[ S_{10} = \frac{10}{2} \times 80,700 = 5 \times 80,700 = 403,500 \]
06
Conclusion
The man's total earnings over the 10-year period is \( 403,500 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Total Earnings
Total earnings refer to the sum of all income received over a particular period. In this example, we consider a man's salary over ten years. Each year, his salary increases by a specific amount, forming a pattern known as an arithmetic sequence.
To calculate total earnings, you need to know:
To calculate total earnings, you need to know:
- The initial annual salary - here, it's \(30,000\).
- The annual raise - here, it's \(2,300\).
- The number of years he works - here, it's \(10\ years\).
Sum of Sequence
The sum of a sequence is a fundamental aspect when dealing with arithmetic sequences, especially when calculating total earnings over time. Here, the sequence is defined by annual salary increases, starting from a set amount and increasing by a constant value.
To find the sum of this sequence, we utilize a formula specifically designed for arithmetic sequences. The formula is:
\[ S_n = \frac{n}{2} \times (2a_1 + (n-1) \cdot d) \]
where:
To find the sum of this sequence, we utilize a formula specifically designed for arithmetic sequences. The formula is:
\[ S_n = \frac{n}{2} \times (2a_1 + (n-1) \cdot d) \]
where:
- \( S_n \) is the sum of the first \( n \) terms.
- \( n \) represents the number of terms - in this case, \(10\ years\).
- \( a_1 \) is the first term - \(30,000\).
- \( d \) is the common difference between terms - \(2,300\).
Arithmetic Progression
An arithmetic progression (also known as an arithmetic sequence) is a sequence of numbers where each term after the first is derived by adding a constant difference from the previous term. This concept is crucial in understanding how salaries increase annually in a structured manner.
For example, the man's salary progression starts at \(30,000\) and increases by \(2,300\) each year. This sequence can be described as:
For example, the man's salary progression starts at \(30,000\) and increases by \(2,300\) each year. This sequence can be described as:
- Year 1: \(30,000\)
- Year 2: \(30,000 + 2,300 = 32,300\)
- Year 3: \(32,300 + 2,300 = 34,600\)
- ... and so on.