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The quantities x and y are positive and are related by the
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19 Aug 2020, 11:13
19 Aug 2020, 11:13
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The quantities x and y are positive and are related by the equation \( xy=k\) where k is a constant. If the value of y increases by 25 percent, then the value of x decreases by what percent?
A. 20%
B. 25%
C. \(33 \frac{1}{3}\) %
D. 75%
E. 80%
Kudos for the right solution and explanation
A. 20%
B. 25%
C. \(33 \frac{1}{3}\) %
D. 75%
E. 80%
Kudos for the right solution and explanation
Re: The quantities x and y are positive and are related by the
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20 Aug 2020, 16:25
20 Aug 2020, 16:25
Let xy=k
Since k is constant that means that any changes in y will come with change in x in order to keep the product of both equal to k
y increases by 25%
so y now is 1.25y
We let our new x be nx, where n is a coefficient.
Therefore
(nx)*(1.25y)=k=xy
1.25n*xy=xy
1.25n=1
n=1/1.25
n=4/5
n=.8
Therefore our new x is nx=0.8x
That is, x decreased by 20%
Final Answer: A
Since k is constant that means that any changes in y will come with change in x in order to keep the product of both equal to k
y increases by 25%
so y now is 1.25y
We let our new x be nx, where n is a coefficient.
Therefore
(nx)*(1.25y)=k=xy
1.25n*xy=xy
1.25n=1
n=1/1.25
n=4/5
n=.8
Therefore our new x is nx=0.8x
That is, x decreased by 20%
Final Answer: A
Re: The quantities x and y are positive and are related by the
[#permalink]
05 Jul 2022, 01:54
05 Jul 2022, 01:54
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