If the ratio of (T + C)/(A+ G) in one strand of DNA is 1.43, same ratio in the complementary strand is :

Pyrimidine/purine ratio on the first strand is 1.43/1 = 143/100So, in the first strand, out of every 243 bases, there are 143 pyrimidines and 100 purinesPurine in one strand always pairs with a pyrimidine in the other strand.So, in the second strand, out of every 243 bases, there must be 100 pyrimidines and 143 purinesPyrimidine/purine ratio on the second strand must be 100/143 = 0.7