In a 35 lbs. mixture, the percentage of pure quinine is 60.how much pure quinine should be added to the mixture so that the adulteration is 36%of the total?
In 35 lbs, 60% is quinine, therefore 40% is adulteration.
i.e. amount of adulteration is 0.4 * 35 = 14 lbs
and amount of quinine is 35 – 14 = 21 lbs
Now add x lbs of pure quinine to the mix.
This gives us 35 + x lbs of mix
Percentage of adulteration is 14/(35+x) * 100 = 36 (i.e. 36%)
14/(35+x) = 0.36
14 = 0.36(35+x)
14 = 12.6 + 0.36x
1.4 = 0.36x
x = 1.4/0.36 = 3.8888... lbs
Answer: Amount of quinine to be added, to give 36% adulteration, would be 3.89 lbs