SOLUTION: At Johnson Middle school, 170 students buy 3 ring binders from school store. This number has been increasing at a rate of about 25 per year. The number of students buying 2 ring bi

Question 357158: At Johnson Middle school, 170 students buy 3 ring binders from school store. This number has been increasing at a rate of about 25 per year. The number of students buying 2 ring binders is 300 and has been decreasing at a rate of about 15 per year. At these rates, when will the number of 2 ring binders sold be half the number of 3 ring binders sold?
Found 2 solutions by checkley77, stanbon:
Answer by checkley77(12844) (Show Source): You can put this solution on YOUR website!
170+25x=2(300-15x)
170+25x=600-30x
25x+30x=600-170
55x=430
x=430/55
x=7.818 yrs. 2 ring bindes will be half as many as the 3 ring binders.
Proof:
170+25*7.818=2(300-15*7.818)
170+195.45=2(300-117.27)
365.45=2*182.73
365.45~365.46
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
At Johnson Middle school, 170 students buy 3 ring binders from school store. This number has been increasing at a rate of about 25 per year.
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#(3 ring) = 170+25x
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The number of students buying 2 ring binders is 300 and has been decreasing at a rate of about 15 per year.
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#(2 ring) = 300-15x
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At these rates, when will the number of 2 ring binders sold be half the number of 3 ring binders sold?
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Equation:
Solve: 300-15x = (1/2)(170+25x)
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600 - 30x = 170+25x
55x = 430
x = 7.82 years
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Cheers,
Stan H.

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