Problema Solution
A bar of metal contains 10% gold; another bar contains 18% gold. How many pounds of each must be used to make a 20 pound bar of 15%?
Answer provided by our tutors
let
x = lbs of the 10% gold bar
y = lbs of the 18% gold bar
the new bar is 20 lbs of 15% gold thus
x + y = 20
0.10x + 0.18y = 0.15*20
by solving the system of equations we find
x = 7.5 lbs
y = 12.5 lbs
click here to see the step by step solution of the system of equations
7.5 lbs of the 10% gold and 12.5 of the 18% gold bar must be used.