Question: Jimmy bought textbooks and workbooks for $122. Cost of one textbook is $20 and cost of one workbook is $11. Write an equation that models the number of textbooks and workbooks Jimmy bought.
A ) 11x + 20y = 122 B ) 20x + 11y = 132 C ) 20x + 11y = 122 D ) x + 11y = 122
Steps to derive
1 (Price of a textbook x Number of textbooks) + (Price of a workbook x Number of workbooks) = Total cost [Verbal model.]
2 Price of one textbook = $20
3 Price of one workbook = $11
4 Total amount Jimmy had = $122
5 Let x be the number of textbooks and y be the number of workbooks Jimmy bought.
6 20x + 11y = 122 [Substitute the values of the variables in step 1.]
7 The linear model for the situation is 20x + 11y = 122.
