Page 107 - Mathematics_F1
P. 107

Hence,  x = 23.                         Simplifying simultaneous equations
                Therefore, the larger number is 23      gives,
                and the smaller number is 7.
                                                          pr =  ) 37000
                                                            + 
                                                            3 ) 83000r =
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                Example 5.39                              p −
                                                        Use substitution method to solve
                Dashi has 83,000  Tanzanian             equations (1) and (2) as follows.
                shillings for shopping. If he buys      From equation (2), expressing p in
                2 ties and 2 shirts, he remains with    terms of r  gives
                9,000 Tanzanian shillings. If he
    Tanzania Institute of Education
                buys 1 tie and 3 shirts he spends
                all the money. Find the price of a        p = 83000 3r−                         (3)
                tie and a shirt.                        Substitute equation (3) into
                                                        equation (1), that is,
                Solution
                Let:   p   be the price of a tie in         83000 3rr      34000
                                                                      +=
                                                                  −
                      Tanzanian shillings.                     83000 2r−  =  34000
                        r  be the price of a shirt in                −  2r =  −  46000
                      Tanzanian shillings.                                      − 46000
                                                                        r =
                It implies that for the first option,                                − 2
                the cost for 2 ties is Tshs  2p  and                                  =  23,000
                the cost for 2 shirts is Tshs  2.r       Hence,  r = 23,000


                Thus, the total cost for  2 ties and 2   Substitute r =  23,000into equation
                shirts is 2p + 2r.                      (3) to obtain the value of p. That is
                For the second option, the cost for             p = 83000 (3 23000)−  ×
                1 tie is Tshs   p  and the cost for 3              83000 69000−
                                                               =
                shirts is Tshs 3.r                                 14000

                                                        Therefore, the price of each tie is
                Therefore, the total cost for 1 tie     14,000 Tanzanian shillings and
    Mathematics Form One  From  this  information,  form  a   Tanzanian shillings.
                and 3 shirts is p + 3r.
                                                        the price of each shirt is 23,000

                system of linear simultaneous
                equations as follows:
                 83000 (2p + −
                                2 ) 9000r =
                
                
                              3 ) 0r =
                 83000 ( p + −
                
                                                 100




                                                                                        25/09/2025   15:01:17
   Mathematics form 1.indd   100                                                        25/09/2025   15:01:17
   Mathematics form 1.indd   100
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