By the way, how to derive the 12 units


Thank so much :slapshead:

This is tough, please help :imdrowning:


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Thanks a Million in advance

Thank you very much

Appreciate your help to solve these questions from Henry Park 2011:


Q7. Cheryl and Serene have some money. If Cheryl gives Serene $20, they will have the same amount of money. If Serene gives Cheryl $25, Cheryl will have twice as much money as Serene. How much money does Serene have.

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