Answer:
Paul is the youngest at 17 years old. Fiona is 20 years old, Sara is 23 years old
Explanation:
Assign variables to the ages.
S = sara's age
F = Fiona's age
P = Paul's age.
S + F + P = 60
S = 3 + F
P = F - 3
(3 + F) + F + (F - 3) = 60
3 + 3F - 3 = 60
3F = 60
F = 20
S = 23
P = 17