SOLUTION: When Chin Ho's age was twice Samy's age, Paul's age was 30. When Paul's age was twice Chin Ho's age, Samy's age was 21. Given that Paul was the oldest among the three persons, find

Let their initials represent their ages.
 
x years ago, Chin Ho was twice Samy's age x years ago, so 
 
C - x = 2(S - x)
 
x years ago, Paul was P - x, so
 
P - x = 30
 
Let's eliminate x from the system of equations:



When we do that we get the equation:

1)     C + P - 2S = 30

y years ago, Paul's age was twice Chin Ho's age y years ago, so
 
P - y = 2(C - y)
 
y years ago, Samy was 21, so
 
S - y = 21

Let's eliminate y from the system of equations:

 

When we do that we get the equation:

2)  -2C + P + S = 21

We now take the system of equations 1) and 2)



and solve for S and C in terms of P,

we get



Therefore when Paul was 62, we substitute 62 for P
in S=P-27 and get S=62-27=35.

So the answer is 35.

[Note: there is no way to determine any of their
ages now, but only that Paul is 27 years older than Samy,
and 24 years older than Chin Ho, which of course makes
Chin Ho 3 years older than Samy.]

Edwin