Solve

 

If I give my brother 5 dollars, then we will have the same amount of money. If instead he gives me 25 dollars, then I'll have twice as much money as he will have. How much money does my brother currently have (in dollars)?     

 

B stands for Brother's money     

M stands for My money     

 

(M – 5)  =  (B + 5)                                 ——>>     M  =  B + 10      (equation 1)     

(M + 25)  =  2 • (B – 25)  =  2B – 50     ——>>     M  =  2B – 75     (equation 2)     

 

Set M (eq 2)  =  M (eq 1)     

 

2B – 75  =  B + 10     

          B  =  85     

 

check answer     

per (eq 1)                 M  =  95     

sub into (eq 2)          95  =  170 – 75     

                                 95  =  95     

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