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

कुल इकाइयां = 13 + 7 = 20। 20 इकाइयां = 100 किग्रा => 1 इकाई = 5 किग्रा। जस्ता (13 इकाइयां) = 13 * 5 = 65 किग्रा।