Zinc = 7/18
Divide 4.9 by 7 = 0.7
Multiply by 18 = 12.6
The answer is 12.6 lbs of alloy. Sorry if I'm wrong
Use subtraction the answer is 44
Since 
(density = mass/volume), we can get the mass/weight of the liquid by integrating the density 
over the interior of the tank. This is done with the integral
which is more readily computed in cylindrical coordinates as
"Minute" is a unit of time, whereas "mile" is a unit of length or distance.
They have different physical dimensions, they measure different quantities,
and they can't be converted one to the other.
If distance could be converted to time, then it would be possible for you ...
or a more mathematically capable acquaintance ... to calculate how many
minutes long your dog's tail is.
