Example 7 - Chapter 4 Class 7 - Expressions using Letter-Numbers (Ganita Prakash)

Transcript

Example 7 A shop rents out chairs and tables for a day’s use. To rent them, one has to first pay the following amount per piece. When the furniture is returned, the shopkeeper pays back some amount as follows. Write an expression for the total number of rupees paid if x chairs and y tables are rented.Given Number of chairs = x Number of tables = y Now, Total amount paid = Amount paid renting out – Amount received after return back Amount paid renting out Amount paid for x chairs = x × 40 = 40x Amount paid for y tables = y × 75 = 75y Total Amount paid renting out = 40x + 75y Amount received after return back Amount received back for x chairs = x × 6 = 6x Amount received back for y tables = y × 10 = 10y Total Amount received back = 6x + 10y Therefore, Total amount paid = Amount paid renting out – Amount received after return back = (40x + 75y) – (6x + 10y) = 40x + 75y – 6x – 10y = (40x – 6x) + (75y – 10y) = 34x + 65y