The ratio of copper and zinc in brass is 13 : 7. How much zinc will be there in 100 kg of brass?

कुल भाग = 13 + 7 = 20। 1 भाग का मूल्य = 100 / 20 = 5 किलोग्राम। जस्ता (7 भाग) = 7 * 5 = 35 किलोग्राम।