an alloy weighing 26 ounces is 70 percent gold . how many ounces of pure gold must be added to create an alloy that is 90 percent gold ?
in 24 ounces , gold is 26 * ( 70 / 100 ) = 18.2 ounces . now we add x ounces of pure gold to make it 90 % gold . so 18.2 + x = ( 24 + x ) * 90 / 100 = > x = 34 . answer is d .
divide(multiply(divide(90, const_100), 26), divide(70, const_100))