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Mike's average on the first five exams in Econ \(1 \mathrm{~A}\) is 88 What must he earn on the next exam to raise his overall average to \(90 ?\)

Short Answer

Expert verified
Mike must score 100 on his next exam to raise his overall average to 90.

Step by step solution

01

Find the total sum of scores

First, we need to find the total sum of Mike's scores on the first five exams. Since his average is 88 and he's taken 5 exams, we calculate the total sum of scores by multiplying his average score by the number of exams. So, the total sum of scores is \(88 * 5 = 440\).
02

Set up the equation

Now, we set up an equation to find the score Mike needs to get on his 6th exam. We know his desired average is 90 and this average will be based on 6 exams - the 5 he's already taken and the one he's yet to take. The equation is thus: \( \frac{440 + x}{6} = 90\). In this equation, 'x' stands for the score Mike should get to earn his desired average.
03

Solve the equation

Multiplying both sides of the equation by 6, we get \(440 + x = 540\). If we solve this for 'x', by subtracting 440 from both sides, we have \(x = 540 - 440\). This results in \(x = 100\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Understanding Average Calculations
The concept of averages is a fundamental part of mathematics, especially useful in assessments like exams. An average provides a single value that summarizes or represents a set of numbers. To calculate the average, sum up all the numbers in your data set, then divide by the number of items in that set.

For instance, Mike's average score for his first five exams is calculated by totaling his scores and dividing by 5, the number of exams. This process simplifies comparison and helps to identify targets, just like Mike needs an average of 90 after six exams.

  • Step 1: Total Scores = Average × Number of Items
  • Step 2: Average = Total Scores / Number of Items

These formulas help us understand the distribution of values and determine what must be achieved to reach a particular average.
Solving the Equation
Equations help us find unknown values by balancing two sides of a statement, using arithmetic operations to maintain equality.

In the exercise, we set up the equation \( \frac{440 + x}{6} = 90 \), where 440 represents the total of known scores, 6 is the total exams, and \'x\' is the unknown score for the 6th exam. The goal is to solve for \'x\'.

  • First, eliminate the fraction by multiplying both sides by 6, getting \( 440 + x = 540 \).
  • Next, isolate \'x\' by subtracting 440 from both sides, leaving \( x = 100 \).

These steps ensure that the mathematical operations lead us directly to the correct and desired outcome.
Mastering Arithmetic Operations
Arithmetic operations are the basic building blocks of all mathematical calculations. These include addition, subtraction, multiplication, and division. Each has its unique purpose and can be used in various scenarios, like solving equations or calculating averages.

In Mike's case, finding out what score he needs involves:

  • Multiplication: Used to find the total current scores by calculating 88 × 5.
  • Addition and Subtraction: Determine the needed score by lining up known totals against the desired overall outcome.
  • Division: Essential in average calculation, showing how individual components contribute to the whole.

Understanding these operations is crucial. They enable the manipulation of numbers to solve problems efficiently and accurately. This foundation supports not just calculations but logical reasoning needed to deduce solutions in broader contexts.

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Most popular questions from this chapter

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