2. Steps to Solving Word Problems 1. Use a variable to represent the unknown quantity 2. Express any other unknown quantities in terms of this variable, if possible. 3. Write an equation, and solve it. 4. State the answer to the problem. 5. Check your answer by substituting in the problem.

3. How many millilitres of 50% acid solution must be mixed with 30% solution to produce 100 ml of 45% solution? Things to Remember: Use a variable to represent the unknown quantity Express any other unknown quantities in terms of this variable, if possible. Write an equation, and solve it. State the answer to the problem. Check your answer by substituting in the problem. Let x represent the amount of 50% solution. Let (100 - x) represent the amount of 30%. Equation: 0.5x + 0.3(100 - x) = 0.45(100) 0.5x + 30 - 0.3x = 45 0.2x + 30 = 45 0.2x + 30 - 30 = 45 - 30 0.2x = 15 0.2x 0.2 15 0.2 = x = 75 ml (Percent Question)

4. How many millilitres of 50% acid solution must be mixed with 30% solution to produce 200 ml of 45% solution? Things to Remember: Use a variable to represent the unknown quantity Express any other unknown quantities in terms of this variable, if possible. Write an equation, and solve it. State the answer to the problem. Check your answer by substituting in the problem. Equation: (Percent Question)

5. How many millilitres of 50% acid solution must be mixed with 30% solution to produce 200 ml of 45% solution? Things to Remember: Use a variable to represent the unknown quantity Express any other unknown quantities in terms of this variable, if possible. Write an equation, and solve it. State the answer to the problem. Check your answer by substituting in the problem. Let x represent the amount of 50% solution. Let (200 - x) represent the amount of 30%. Equation: 0.5x + 0.3(200 - x) = 0.45(200) 0.5x + 60 - 0.3x = 90 0.2x + 60 = 90 0.2x + 60 - 60 = 90 - 60 0.2x = 30 0.2x 0.2 30 0.2 = x = 150 ml (Percent Question)

6. A woman travels a certain distance by motor scooter at 50 km/h and returns at 60 km/h. Find the distance between the two places if the total travelling time was 11h. Things to Remember: Use a chart to diagram information Use a variable to represent the unknown quantity Express any other unknown quantities in terms of this variable, if possible. Write an equation, and solve it. State the answer to the problem. Check your answer by substituting in the problem. 11x 11 3300 11 = x = 300 km (Distance, Time Question) D (km) S (km/h) T (h) X50 x60 Equation: x 50 x 60 x 50 x 60 = + 11 ) x 50 ( 300 ) x 60 ( 300=+300(11) 6x + 5x = 3300 11x = 3300

7. A woman travels a certain distance by motor scooter at 40 km/h and returns at 70 km/h. Find the distance between the two places if the total travelling time was 13h. Things to Remember: Use a chart to diagram information Use a variable to represent the unknown quantity Express any other unknown quantities in terms of this variable, if possible. Write an equation, and solve it. State the answer to the problem. Check your answer by substituting in the problem. (Distance, Time Question) D (km) S (km/h) T (h) Equation:

8. A woman travels a certain distance by motor scooter at 40 km/h and returns at 70 km/h. Find the distance between the two places if the total travelling time was 13h. Things to Remember: Use a chart to diagram information Use a variable to represent the unknown quantity Express any other unknown quantities in terms of this variable, if possible. Write an equation, and solve it. State the answer to the problem. Check your answer by substituting in the problem. 11x 11 3640 11 = x = 330.91 km (Distance, Time Question) D (km) S (km/h) T (h) X40 x70 Equation: x 40 x 70 x 40 x 70 = + 13 ) x 40 ( 280 ) x 70 ( 280=+280(13) 7x + 4x = 3640 11x = 3640

9. CLASS WORK ► Check solutions to Lesson 3(2) ► Copy down examples ► Do Lesson 3(3) Assignment to hand in.