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Homework Statement
A rectangular object has a fixed length of 1m. The height is increasing by 12 cm/min. Find the rate that the width must change so that the volume remains constant at 16 000cm^3 when the height is 10 cm
The Attempt at a Solution
So here's what I tried:
The Volume= Lenth x Width x Height
V = x y z Since x is fixed at 100 , V= 100 y z
dV/dt = 100y dz/dt +100 z dy/dt = 0
z dy/dt = -ydz/dt
(10) (12) = - y dz/dt
When x= 100 and z= 10 and V=16000 , y = 16
dz/dt = - (10)(12)/y = - 120/16 = -7.5 cm/min
However, I don't even know if I am taking the right approach... Please give me assistance