If a national campaign aims to reduce pollution by 15% each year and the current
Practice Questions
Q1
If a national campaign aims to reduce pollution by 15% each year and the current pollution level is 200 units, what will be the pollution level after 2 years? (2020)
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Questions & Step-by-Step Solutions
If a national campaign aims to reduce pollution by 15% each year and the current pollution level is 200 units, what will be the pollution level after 2 years? (2020)
Step 1: Identify the current pollution level, which is 200 units.
Step 2: Determine the reduction percentage, which is 15%. Convert this percentage to a decimal by dividing by 100: 15% = 0.15.
Step 3: Calculate the remaining pollution after the reduction. This is done by subtracting the reduction from 1: 1 - 0.15 = 0.85.
Step 4: To find the pollution level after 1 year, multiply the current pollution level by the remaining percentage: 200 * 0.85 = 170 units.
Step 5: Now, repeat the process for the second year. Again, multiply the pollution level after 1 year by the remaining percentage: 170 * 0.85 = 144.5 units.
Step 6: Round the final pollution level to the nearest whole number: 144.5 rounds to 145.
Exponential Decay – The question tests the understanding of exponential decay, where a quantity decreases by a fixed percentage over time.
Percentage Reduction – It assesses the ability to apply percentage reduction to a given initial value over multiple time periods.
