Question 495007
John is 5 years older than Mary. 
In 10 years, twice John's age decreased by Mary's age is 35, and John's age will be twice Mary's current age. Find their ages now.
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If x is Mary's age now and y is John's age now, which system of equations could not be used to solve the problem?
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y = x + 5
2(y+10)-(x-10) = 35
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Substitute for "y" and solve for "x":
2(x+15) -x+10 = 35
x + 25 = 35
x = 10 yrs old (Mary's age now)
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y = x+5
y = 15 yrs old (John's age now)
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Cheers,
Stan H.
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