ALWAYS use these steps when solving word problems: 1. Problem Solving Steps ALWAYS use these steps when solving word problems: What are you trying to find? What do you know? Given in the problem? From formulas and prior knowledge? 3. How will you solve the problem? 4. Did you answer the original question?
I DO Example 1: Let w represent the width of a rectangle. The length of a rectangle is seven times the width. Evaluate the expression and find the length of a rectangle with a width of 15 inches. Length = 7w inches 2. Examples What are you trying to find? Length of rectangle What do you know? Given in the problem? Length = 7w inches Units are inches The width is 15 inches w = width From formulas and prior knowledge? Shape of a rectangle
I DO Example 1: Let w represent the width of a rectangle. The length of a rectangle is seven times the width. Evaluate the expression and find the length of a rectangle with a width of 15 inches. Length = 7w inches 2. Examples 3. How will you solve the problem? Length = 7w inches Length = 7(15) = 105 inches Did we answer the original ? Trying to find length and it is 105 inches
WE DO Example 2: Let w represent the width of a rectangle. The length of a rectangle is five more than two times the width. Evaluate the expression and find the length of a rectangle with a width of 12 inches. Length = 5 + 2w inches 2. Examples What are you trying to find? Length of rectangle What do you know? Given in the problem? Length = 5 + 2w inches Units are inches The width is 12 inches w = width From formulas and prior knowledge? Shape of a rectangle
WE DO Example 2: Let w represent the width of a rectangle. The length of a rectangle is five more than two times the width. Evaluate the expression and find the length of a rectangle with a width of 12 inches. Length = 5 + 2w inches 2. Examples 3. How will you solve the problem? Length = 5 + 2w inches Length = 5 + 2(12) 5 + 24 = 29 inches Did we answer the original ? Trying to find length and it is 29 inches
I DO Example 3: Bart’s uncle is 5 more than four times his age. Let b represent Bart’s age. Write and evaluate an expression for his uncle’s age if Bart is 10 years old. 2. Examples What are you trying to find? Bart’s uncle’s age if he is 10 years old What do you know? Given in the problem? Bart’s uncle is 5 more than 4x his age b is Bart’s age Bart is 10 years old From formulas and prior knowledge? Age is measured in years
I DO Example 3: Bart’s uncle is 5 more than four times his age. Let b represent Bart’s age. Write and evaluate an expression for his uncle’s age if Bart is 10 years old. 2. Examples 3. How will you solve the problem? Bart’s uncle’s age = 5 + 4b Bart’s uncle’s age = 5 + 4(10) 5 + 40 = 45 years old Did we answer the original ? Trying to find uncle’s age and it is 45 yrs old
WE DO Example 4: Abraham J Simpson is 30 less than three times Homer’s age. Let h represent Homer’s age. Write an evaluate an expression for Abraham’s age if Homer is 41. 2. Examples What are you trying to find? Abraham’s age if Homer is 41 What do you know? Given in the problem? Abraham is 30 less than 3times Homers age h is Homer’s age Homer is 41 From formulas and prior knowledge? Age is measured in years
WE DO Example 4: Abraham J Simpson is 30 less than three times Homer’s age. Let h represent Homer’s age. Write an evaluate an expression for Abraham’s age if Homer is 41. 2. Examples 3. How will you solve the problem? Abraham’s age = 3h – 30 Abraham’s age = 3(41) - 30 123 – 30 = 93 years old Did we answer the original ? Trying to find Abraham’s age and it is 93 yrs old
2. I DO Examples MAKE SURE YOU ANSWER THE ACTUAL QUESTION! Example 5: Vasu is building an aquarium where the base length, in inches, must be 10 more than 3 times the width. Let w represent the width of the aquarium. Find the perimeter of the base of the aquarium if the width is 12 inches. 2. Examples MAKE SURE YOU ANSWER THE ACTUAL QUESTION! What are you trying to find? Perimeter of the aquarium base What do you know? Given in the problem? Length is 10 more than 3 times width W is the width Width is 12 inches From formulas and prior knowledge? Perimeter means to add all four sides: 2W + 2L We can write an expression for length
2. 2. I DO Examples MAKE SURE YOU ANSWER THE ACTUAL QUESTION! Examples Example 5: Vasu is building an aquarium where the base length, in inches, must be 10 more than 3 times the width. Let w represent the width of the aquarium. Find the perimeter of the base of the aquarium if the width is 12 inches. 2. Examples MAKE SURE YOU ANSWER THE ACTUAL QUESTION! 2. Examples 3. How will you solve the problem? Length = 10 + 3w Length = 10 + 3(12) 10 + 36 = 46 inches Did we answer the original ? NO! Didn’t find perimeter! P = 2L + 2W 2(46) + 2(12) = 92 + 24 = 116 inches