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RATIONAL WORD PROBLEMS TO SOLVE RATIONAL WORD PROBLEMS.

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Presentation on theme: "RATIONAL WORD PROBLEMS TO SOLVE RATIONAL WORD PROBLEMS."— Presentation transcript:

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2 RATIONAL WORD PROBLEMS

3 TO SOLVE RATIONAL WORD PROBLEMS

4 TO SOLVE RATIONAL WORD PROBLEMS 1. Set up the unknowns in one variable.

5 TO SOLVE RATIONAL WORD PROBLEMS 1. Set up the unknowns in one variable. 2. Set up an equation for the situation.

6 TO SOLVE RATIONAL WORD PROBLEMS 1. Set up the unknowns in one variable. 2. Set up an equation for the situation. 3. Multiply by the common denominator to clear out fractions.

7 1. Set up the unknowns in one variable. 2. Set up an equation for the situation. 3. Multiply by the common denominator to clear out fractions. 4. Solve the remaining equation for the variable. TO SOLVE RATIONAL WORD PROBLEMS

8 1. Set up the unknowns in one variable. 2. Set up an equation for the situation. 3. Multiply by the common denominator to clear out fractions. 4. Solve the remaining equation for the variable. 5. State final answers in real world terms. TO SOLVE RATIONAL WORD PROBLEMS

9 Most tunnels are drilled using tunnel-boring machines that begin at both ends of the tunnel. Suppose a new underwater tunnel is being built and one tunnel-boring machine alone can finish the tunnel in 4 years. A different type of machine can tunnel to the other side in 3 years. If both machines start at opposite ends and work at the same time, when will the tunnel be finished?

10 Let x = number of years together

11 Equation:

12 Let x = number of years together Equation:

13 Solve equation: multiply by common denominator (4)(3)(x).

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18 If both machines work toward each other it will take 1.7 years to finish the tunnel.

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20 A car travels 300 km in the same time that a freight train travels 200 km. The speed of the car is 20 km/h more than the speed of the train. Find the speed of the car and the speed of the train.

21 Let x = speed of train Let x + 20 = speed of car

22 A car travels 300 km in the same time that a freight train travels 200 km. The speed of the car is 20 km/h more than the speed of the train. Find the speed of the car and the speed of the train. Let x = speed of train Let x + 20 = speed of car

23 Use the formula d = rt. Solve for t.

24 t = d/r Use the formula d = rt. Solve for t.

25 t = d/r Use the formula d = rt. Solve for t.

26 t = d/r Use the formula d = rt. Solve for t.

27 t = d/r Use the formula d = rt. Solve for t.

28 Solve: multiply by the common denominator (x + 20)(x).

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33 Speed of train = x = 40 km/h

34 Speed of car = x + 20 = 60 km/h

35 Speed of train = x = 40 km/h Speed of car = x + 20 = 60 km/h

36 One electronic reader can read a deck of punched cards in half the time of another reader. Together they can read the deck in 8 minutes. How long would it take each reader alone to read the deck?

37 Let x = first reader time

38 One electronic reader can read a deck of punched cards in half the time of another reader. Together they can read the deck in 8 minutes. How long would it take each reader alone to read the deck? Let x = first reader time Let 2x = second reader time

39 One electronic reader can read a deck of punched cards in half the time of another reader. Together they can read the deck in 8 minutes. How long would it take each reader alone to read the deck? Let x = first reader time Let 2x = second reader time

40 Solve: multiply by common denominator (x)(8)

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43 First reader = x = 12 minutes Second reader = 2x = 24 minutes

44 One pipe can fill a tank in 6 hours while another can empty it in 2 hours. How long will it take to empty the full tank if both pipes are open at once?

45 Let x = time to empty full tank

46 One pipe can fill a tank in 6 hours while another can empty it in 2 hours. How long will it take to empty the full tank if both pipes are open at once? Part empty - Part fill = Total empty Let x = time to empty full tank

47 One pipe can fill a tank in 6 hours while another can empty it in 2 hours. How long will it take to empty the full tank if both pipes are open at once? Part empty - Part fill = Total empty Let x = time to empty full tank

48 Solve: multiply by the common denominator (x)(6).

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52 It will take 3 hours to empty the tank.

53 1. Set up variables. 2. Set up equation. 3. Multiply by the common denominator. 4. Solve for variables. 5. Define final answers. TO SOLVE RATIONAL WORD PROBLEMS

54 PRACTICE TIME GO FOR IT!!!!


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