Answer:
Jiri is 34 years old.
Step-by-step explanation:
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.
To work out the estimate cost you need do 200 * 5=$1000
then I used a calculator and the actual answer is $895