Given that y varies directly as x and inversely as z^(2). If y is increased by 60% and z is decreased by 25%, find the percentage change of x.
The answer is -10%
(z^(2))= the square of z.
* Please give the steps and the method to do it in a simple way. Answers are not accepted if the answer is not correct. thx!!!
University Maths Question.
2010-07-27 6:47 am
回答 (1)
2010-07-27 7:23 am
✔ 最佳答案
from the given, y=kx/z^2therefore x=yz^2/k = Kyz^2, where k and K=1/k are constants
For y increased by 60% and z decreased by 25%, let the new value of x be x'
x' = K(1.6y)(0.75z)^2 = K(0.9 yz^2) = 0.9 (Kyz^2) = 0.9x
percentage change
= (new value - old value)/old value *100%
= (x' -x)/x *100%
=(0.9 x - x)/x *100%
= -0.1 *100%
= -10%
Therefore the answer is -10% #
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