Answer:
a. 1996
Explanation:
Let Paul's age in 2000 be P
Let Bilko's age in 2000 be B
Statement: Paul was twice as old as his brother Biko in 2000 means
P = 2B (1)
In 2008 Paul was only four years older than his brother.
Since 2008 is 8 years from 2000, both Paul and Bilko have aged 8 years
Paul's age in 2008 = P + 8
Bilko's age in 2008 = B + 8
Statement: In 2008 Paul was only four years older than his brother means
P + 8 = B + 8 - 4
P = B + 4 (2)
Given these two equations (1) and (2)
Substitute P = 2B from (1) in (2):
2B = B + 4
==> 2B - B = 4
==> B = 4
Therefore in 2000, Paul was 8 years old and Bilko was 4 years old
Bilko's year of birth = 2000 - 4 = 1996