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Access to Safe Water
Complete these exercises with information from Chart 1.

Chart 1 Exercises with Answers


Percentage of the World’s Population With and
Without Access to Safe Water, 1990–96

1. Study Chart 1, which shows world population and access to safe water and answer the following questions.

  1. What percentage of the world’s population in 1990–96 did not have access to safe water? [25%]
  2. The total population of the world in 1998 was approximately 5.9 billion. If the percentage of people with access to safe water stays the same as it was in 1990-96, use your answer to question 1a and calculate how many people were without safe water in 1998? (Divide the percentage by 100 to get a decimal, then multiply the total population of the world by the decimal figure). [approximately 1.48 billion]
  3. How many people did have access to safe water? [5.9 billion – 1.48 billion = 4.42 billion]

2. In the year 2015, the population of the world is projected to reach 7.1 billion.

  1. If the number of people with access to safe water stays the same as it was in 1990–96, what percentage of the world’s population in 2015 will have access to safe water? (Divide 4.42 billion by 7.1 billion and multiply by 100.) [62%]
  2. How does this percentage compare with that shown in Chart 1? [It is smaller.] Based on this information, would the population in 2015 be better off, worse off, or the same? Explain. [They would be worse off, because the percentage of the population with safe water would have decreased from 75% to 62%, and safe water is necessary for life.]

3. Statistics can be powerful tools that help us understand our world. But statistics must be used carefully, and people must understand what the data do and do not tell us.

It is the year 2000. You are running for reelection after two five-year terms as mayor of a city of 800,000 people. In 1990, the population was 600,000, and at that time 37 percent of the population in the city had access to safe water. In the year 2000, 40 percent of the population in the city now have access to safe water.

  1. Did the percentage of population with access to safe water and sanitation increase or decrease during your time as mayor? [It increased.] By how much? [3%, from 37% to 40%]
  2. Calculate the number of people with access to safe water in 1990. [600,000 x .37 = 222,000] Calculate the number of people with access to safe water in 2000. [800,000 x .40 = 320,000] Did the number of people with access to safe water increase or decrease during your time as mayor. [It increased.] By how much? [320,000 – 222,000 = 98,000 people]
  3. Did the number of people without access increase or decrease? (Find the percentage of the population without access by subtracting the percentage of the population with access from 100%, convert the percentage into a decimal, and then follow the calculations you used in question 2b.) [It increased.] By how much? [102,000 people: 800,000 x .60 = 480,000; 600,000 x .63 = 378,000; 480,000 – 378,000 = 102,000 people]
  4. As mayor, what can you say to voters about the progress you have made in the area of safe water and sanitation? [Possible answer: "Since I took office, 98,000 more people have access to safe water. The share of the population with access to safe water has increased from 37% to 40%."]
  5. What might your challenger say to voters about the lack of progress you have made? [Possible answer: "The current mayor is not doing her job. Today, 102,000 more people lack access to safe water than in 1990. More people are suffering."]
  6. What can happen if statistics are not used carefully? [They may be used to misrepresent or distort the facts.]
  7. What kinds of problems might make it difficult to provide safe water to people in urban areas where populations are growing rapidly? [Possible answers: Too many people may need services too quickly; there may be a lack of money, materials, expertise, and skilled workers to lay pipe or repair leaks; local political leadership may not be able or willing to mobilize resources.]
Explore Chart 1:

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