gmatt1476
Alan and Sue have each been saving one dollar a day and will continue to do so for the next month. If Sue began saving several days before Alan, in how many days from today will Alan have saved one-half as much as Sue?
(1) As of today, Alan has saved 7 dollars and Sue has saved 27 dollars.
(2) Three days from today, Alan will have saved one-third as much as Sue.
DS89302.01
Question: Alan and Sue have each been saving one dollar a day and will continue to do so for the next month. If Sue began saving several days before Alan, in how many days from today will Alan have saved one-half as much as Sue?
Let’s say \($a\) is the total amount of dollar that Sue saved earlier than Alan, \($x\) is the total amount of dollar,including today, Sue and Alan started to save at the same time, and \($y\) is the total amount of dollar that Sue and Alan will save in the future.We want to know that in how many days from today will Alan have saved one-half as much as Sue.
Therefore, when \($(x+y)\) equals to \($\frac{a+x+y}{2}\), the value of \(y\) will indicate how many days have passed from today that Alan have saved one-half as much as Sue.
(1) As of today, Alan has saved 7 dollars and Sue has saved 27 dollars.
-> At the end of today, Alan has saved \(x=7\), and Sue has saved \(a+x=27\).
-> Substitute to the original equation, \(7+y=\frac{27+y}{2}\)->\(y=13\).
-> Therefore, in 13 days from today, Alan will save one-half as much as Sue.
-> Sufficient
(2) Three days from today, Alan will have saved one-third as much as Sue.
-> \(x+3=\frac{a+x+3}{3}\)
-> we can’t find value of \(x\) and \(a\)
-> Insufficient
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