Problema Solution
Quantity z varies jointly with x and the cube of y. If z is 15 when x is 5 and y is 2, find z when x is 2 and y is 3.
Answer provided by our tutors
Quantity z varies jointly with x and the cube of y means
z = k*x*y^3
z is 15 when x is 5 and y is 2
15 = k*5*2^3
by solving we find
k = 0.375
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for x = 2 and y = 3 we have
z = 0.375*2*3^3
z = 20.25
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