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My weight increased by \(1 \%\) in January and \(1 \%\) in February, so my increase in weight over the two months is \(2 \%\).

Short Answer

Expert verified
Hence, the total increase over the two months is 2.01%, not 2%.

Step by step solution

01

Assume a Starting Weight

In order to solve this problem, it is easier to take a starting weight. Without loss of generality, let's assume the weight at the start, in December, is 100 kg.
02

Calculate January Weight

In January there is an increase of 1%. Therefore, the weight at the end of January would be the starting weight (in December), plus a 1% increase. So, it is \(100 kg + 1\% \times 100 kg = 101 kg\)
03

Calculate February Weight

In February the weight increases by another 1%, but this is 1% of the new weight at the end of January, not the original weight. Thus, the weight is now \(101 kg + 1\% \times 101 kg = 102.01 kg\)

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Key Concepts

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

Percentages in Mathematics
Percentages are essential tools in mathematics and everyday life to compare quantities, express proportions, and understand changes. They are your go-to when you aim to measure growth, discount, interest rates, or, as in the exercise, weight increase. A percentage can be viewed as a fraction of 100. For instance, if we say 50%, we mean 50 out of every 100, or simply half. When a weight increases by 1%, it essentially means that for every 100 units of weight, an additional one is added.

In problems relating to consecutive percentage increases, it is crucial to remember that each percentage increase is applied to the new amount, not the original. This is a common error when intuitively thinking about percentage changes, as failing to account for this would lead to understating the total growth. Here's a useful tip for solving such problems: convert the percentage into a decimal by diving by 100 and using this multiplier to calculate the increased amount. For example, a 1% increase on 100 kg involves multiplying 100 by 0.01 (which is 1/100) and then adding this to the original weight.
Mathematical Problem Solving
Problem solving in mathematics is a systematic process that involves understanding the problem, devising a plan, carrying out that plan, and then looking back to check the results. One effective strategy is breaking down a complex problem into simpler parts, much like the step-by-step solution applied in our example.

By starting with an assumed weight of 100 kg, the problem simplifies the calculation and makes the concept of percentage increase more digestible. The solver has cleverly chosen 100 kg as the starting point because percentages of 100 are straightforward to calculate. This is a useful approach when dealing with percentage problems, as it eliminates the complexity associated with arbitrary starting numbers and allows for easier mental calculations.

Calculating Increases Sequentially

How a percentage change affects a quantity depends on the value to which it is being applied, which can introduce complexity when dealing with multiple successive changes. In our example, the month-to-month increase isn't additive in the traditional sense because the base to which the percentage is applied changes, demonstrating the importance of sequential calculations.
Mathematical Reasoning
Mathematical reasoning is the ability to use logical thinking to analyze a problem and come to a conclusion. It's what helps you understand that a 1% increase over two months does not simply equal a 2% total increase – it's slightly more because the second increase is compounded on the first. It is this type of reasoning that underpins the approach to our exercise's solution.

The first 1% increase on the initial weight is straightforward, but the second 1% requires you to consider the higher starting point. Recognizing that, one uses multiplication to calculate 1% of the new weight and add it to January's result.

Challenge Common Misconceptions

Through mathematical reasoning, you can challenge common misconceptions about percentages. Considering that successive increases apply to the updated values, and not the original, plays a crucial role in accurate calculations. This reasoning showcases the importance of the underlying principle that percentage increases are multiplicative rather than additive.

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