Exam 3: Numbers in the Real World

Use scientific notation to solve the problem. -A computer can do one calculation in $1.4 \times 10 ^ { - 7 }$ seconds. How long would it take the computer to do a trillion (1012) calculations?

Use scientific notation to perform the following operations. Leave your answer in scientific notation. - $\left( 5 \times 10 ^ { - 3 } \right) \div \left( 10 \times 10 ^ { - 4 } \right)$

Carry out the indicated operation and give your answer with the specified number of significant digits. - $816 \div 0.0538$ ; 1 significant digit

Solve the problem. -The table below shows the result of a polygraph test conducted on 2000 college students. Students were asked whether they had ever cheated on a test. All of them denied having cheated. Use the Table to answer the question. Test finds student lying Test finds student truthful Total Has cheated 82 12 94 Has not cheated 200 1706 1906 Total 282 1718 2000 What percentage of those that were found to be lying were actually telling the truth?

Write the percentage as a fraction or decimal, as indicated. -Write as a decimal. 78\%

Answer the question. -Two candidates for governor of a state differ in their accounts of the state's economy during the incumbent's term. The incumbent claims that during his four-year term the economy has Improved, citing a rise in the median household income from $33,000 to $34,500. The challenger Claims that the economy has declined, citing that the buying power of families in the state has Declined during the four years. Which of the following best explains how both candidates can be Right?

Answer the question. -Find the scale ratio for a map if 3 centimeters on the map represents 0.6 kilometer on the ground.

Measurements are made at two different times. Find the absolute change and then find the percentage change. Roundanswers to the nearest tenth if necessary. -In 1960, in the town of Thornton the percentage of 50 year old women that had never been married was 9.5%. Last year, the percentage of 50 year old women that had never been married was 24.8%.

Use scientific notation to perform the following operations. Leave your answer in scientific notation. - $\left( 8 \times 10 ^ { 4 } \right) \times \left( 3 \times 10 ^ { 2 } \right)$

True or false? -If 28% of the students in Mr. Harris's class speak Spanish and 7% speak French, then 35% must speak either Spanish or French

True or false? -If you score 70% on the midterm math exam and 80% on the final exam, your overall score will be greater than 75%. Assume that the final counts for 60% of the grade and that the midterm counts for 40% of the grade.

Write the word or phrase that best completes each statement or answers the question.For the given measurement, briefly describe any likely sources of random error and any likely sources of systematicerror. -An agency wishes to determine the number of unemployed people in a town. They conduct a mini-census by delivering a survey to every household in the town, asking for information about household members. The information is entered into a computer.

True or false? -Given that Sue's weight increased from 120 lb to 132 lb and that Mark's weight increased from 150 lb to 165 lb, we can say that in absolute terms, Mark's weight increased more, but that in relative terms, Sue's weight increased more.

Write the number in scientific notation. -110,000

Determine whether the source of error represents random or systematic error. -You time how long you spend working out each day. Your watch is running slow and loses one minute each hour.

Determine by what factor the numbers differ. In other words, determine how many times larger the first number is thanthe second. -400 million, 8 trillion

Solve for the percentage in the problem. Round to the nearest tenth of a percent. -$18.93 is % of $175.72.

Write the percentage as a fraction or decimal, as indicated. -Write as a decimal. $0.97 \%$

Measurements are made at two different times. Find the absolute change and then find the percentage change. Roundanswers to the nearest tenth if necessary. -Two years ago I earned $88,000. Last year I earned $56,000.

Write the number in scientific notation. -The hard drive of the computer has a capacity of 20 gigabytes. (The prefix giga means 1 billion).