8:00 GED Math Week 2 Monday

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Intro to Ratio and Proportion

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8:00 GED Math Week 2 Monday

  1. 1. • 1. Discuss Fractions “Quiz” with your table• 2. Intro to Ratio and Proportion• 3. Setting Up Ratios• 4. Proportion• 5. Proportion Word Problems
  2. 2.  A ratio is a comparison of numbers by division. A ratio can be written with the word to, with a colon (:), or as a fraction. Should always be reduced (simplifying)
  3. 3. 3 to 2 3:2
  4. 4.  The numbers in a ratio MUST be written in the order the problem asks for. Always reduce a ratio to lowest terms. When a ratio is an improper fraction, DO NOT change it to a mixed number.
  5. 5.  1. Read the problem carefully. 2. Pay attention to the order the question wants you to write the ratio. 3. Set up the ratio appropriately. 4. REDUCE!!!!!
  6. 6.  Evelyn earns $2400 a month. She pays $600 a month in rent. What is the ratio of her income to her rent.Make a ratio with her income first (in thenumerator) and her rent second. income 2400 24 4 For every $4 she makes, rent 600 6 1 She spends $1 on rent
  7. 7.  In a factory, there are 150 men and 100 women working.To compare these facts, write a ratio of men towomen working in the factory. men 150 15 3 men women 100 10 2 women
  8. 8.  1. 24:30 = 200:125 = 28 = 21
  9. 9.  2. 3.4 = 1.7 4 to 1000 = $560 to $320
  10. 10.  3.Alvaro makes $600 a week and saves $60 a week. What is the ratio of the amount he makes to the amount he saves?
  11. 11.  4. For Alvaro, in problem 3, what is the ratio of the amount he saves to the amount he makes?
  12. 12.  5. There are 24 students in Sam’s English class. Four of the students speak Armenian as a first language. What is the ratio of Armenian speakers to the total number of students in the class?
  13. 13.  6. Anna drove 110 miles on 22 gallons of gas. What is the ratio of the distance she drove to the number of gallons of gas she used?
  14. 14. When you are not givenboth numbers youneed, you may have todetermine one of thenumbers.
  15. 15.  On a test with 20 problems, Maceo got 2 problems wrong. What was the ratio of the number of problems he got right to the total number of problems?Step 1: Find the numberof problems he got right. 20-2= 18problems right.Step 2: Make a ratio of right 18 9the number of problems total 20 10he got right to the totalnumber of problems.Reduce.
  16. 16.  1. A GED class of 20 students has 12 women. A.) What is the ratio of the number of women to the total number of students? B.) What is the ratio of the number of men to the total number of students? C.) What is the ratio of the number of men to the number of women? D.) What is the ratio of the number of women to the number of men?
  17. 17.  2. At Baxter Electronics there are 105 union workers and 45 nonunion workers. A.) What is the ratio of the number of union workers to the total number of workers? B.) What is the ratio of the number of nonunion workers to the total number of workers? C.) What is the ratio of the number union workers to the number of nonunion workers? D.) What is the ratio to the number of workers to the number of union workers?
  18. 18.  From a total yearly budget of $18,000,000, the city of McHenry spends $3,000,000 on education. What is the ratio of the amount spent on education to the amount not spent on education?
  19. 19.  4. A math test of 50 questions included 15 fraction problems and 5 decimal problems. What is the ratio of the total number of fraction and decimal problems to the number of questions on the test?
  20. 20.  5. There are 1213 registered voters in Paul’s village. During the last election 887 people actually voted. Which of the following is approximately the ratio of the number of people who voted to the total number of registered voters?
  21. 21. • A statement that says two ratios (or two fractions) are equal. Proportion Statements 2:4 = 1:2
  22. 22. • Remember: cross products of equal fractions are equal 4=4
  23. 23. • Each of the four numbers in a proportion is called an ELEMENT or a TERM.• A letter usually represents the missing term.
  24. 24. • Step 1: Write a statement with two equal cross products.• Step 2: Divide both sides of the statement by the number in front of the missing term. =
  25. 25. • Solve for c in• Step 1: Write a statement with two equal cross products.• Step 2: Divide both sides of the statement by the number in front of the missing term.
  26. 26. • Solve for y in the proportion 5:y=2:8• Step 1: Write a statement with two equal cross products.• Step 2: Divide both sides of the statement by the number in front of the missing term.
  27. 27. If 12 yards oflumber cost •$40, how much do30 yards oflumber cost?Step 1: Set up tworatios of yards to cost.Step 2: Find bothcross products.Step 3: Divide bothsides of theproportion.
  28. 28. Carlos got 2 problems •wrong for every 5 problemsright on a test. How manyproblems did Carlos getwrong if there were 35problems on the test? • Step 1: Set up two ratios of wrong to total • Step 2: Find both cross products. • Step 3: Divide both sides of the proportion.
  29. 29. The ratio of the number of men to the number of • women working in the county hospital is 2:3. If 480 women work in the hospital, how many men work there?• Step 1: Set up two ratios of ________to ________.• Step 2: Find both cross products.• Step 3: Divide both sides of the proportion.
  30. 30. Manny Drove 110 miles in2 hours. Which •expression shows thedistance he can travel in 5hours if he drives at thesame speed?• Step 1: Set up two ratios of ________to ________.• Step 2: Find both cross products.• Step 3: Divide both sides of the proportion.

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