math problem

 

Five times a number is divided by 7 more than the original number. If the result is 12, then what was the original number?  

 

 

Let X stand for the original number. 

 

The terms of the problem                     (5 • X) / (X + 7)  =  12  

 

Multiply both sides by (X + 7)                 5X  =  12X + 84  

 

Subtract 12X from both sides                –7X  =  84  

 

Divide both sides by –7                             X  =  –12  

 

 

Check answer as follows:  

 

Plug –12 into original equation                (5 • –12) / (–12 + 7)  =  12      

 

                                                                 (–60) / (–5)  =  12   answer is confirmed  

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