<PRE><B>Question 72964</B>
the mass of an object varies jointly within its density and its volume. If 156 grams of iron has a volume of 20 cm^3 and a density of 7.8 gm/cm^3, what is the volume of 312 grams of iron with the same density? 
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m = k dv
156 = k*7.8*20
k=156/156
k=1
EQUATION
m = dv
312 = 7.8v
v= 40 cm^3
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Cheers,
Stan H.</PRE>