solve

 

A candy bar and a piece of bubble gum together cost 1.50.  The candy bar costs a dollar more than the bubble gum.  How much does the piece of bubble gum cost, in cents?     

 

Let C stand for the candy     

Let G stand for the gum     

 

C + G = 150     (stated as ¢ throughout to keep things straight)     

C = G + 100     

 

substitute G+100 for C in the first equation     

 

                 (G + 100) + G  =  150     

                         2G + 100  =  150     

                                   2G  =  150 – 100     

                                   2G  =  50     

                                     G  =  25     

_.