The first thing you want to do is subtract 6 from 74, since Pamela is 6 years older than jiri and their ages summarized is 74, this spans the age difference.
Next you want to divide the answer you got earlier (68, from subtracting 6 from 74) and divide it by two since there are two people. The answer is 34, Jiri is 34 years old and Pamela is 40 years old.
