Country A has a higher inflation than country B. Since, the exchange rate is fixed, it is advantageous for country B to export goods to country A. Similarly, it is advantageous for country A to import goods from country B. On the other hand, it would be expensive for country A to export goods to country B. Thus, country A will have trade deficit as it will import more goods as compared to exports, from country B. Country B will import less goods as compared to exports, from country A. Hence, there is a trade surplus in country B.