According to the relative purchasing power parity theory, high inflation in country A and low inflation in country B will cause the value of country A's currency to appreciate relative to that of country
B.

Relative Purchasing Power Parity

Relative Purchasing Power Parity (RPPP) is an economic theory which postulates that the rate at which the exchange rate between two currencies will change over time is equivalent to the rate at which their purchasing power converges, essentially due to inflation rates differences.

Inflation

The rate at which the general level of prices for goods and services is rising, eroding purchasing power over time.