Question 1016472
How much pure gold added to 180 ounces of 14-karat gold (14/24 pure) will make 16-karat gold.
:
let x = amt of pure gold required
180(14/24) + x = (16/24)(x + 180)
105 + x = {{{2/3}}}(x + 180) 
105 + x = {{{2/3}}}x + 120
x - {{{2/3}}}x = 120 - 105
{{{1/3}}}x = 15
multiply both sides by 3
x = 45 ounces of pure gold