The given statement states that not all costly commodities are of good quality, which implies that cost cannot be the sole indicator of quality. Based on this, the inference that quality cannot be judged by cost is indeed true.
Thus, the correct answer is (A) a
Arun’s present age in years is 40% of Barun’s. In another few years, Arun’s age will be half of Barun’s. By what percentage will Barun’s age increase during this period?