Answer:
Age of Cathy = 19
Step-by-step explanation:
Find:
Sum of their ages = 54
Assume;
Age of Andrea = x
Age of Beth = x + 1
Age of Cathy = x + 2
Sum of their ages = x + x + 1 + x + 2
54 = 3 x + 3
3 x = 51
x = 17
Age of Cathy = x + 2
Age of Cathy = 17 + 2
Age of Cathy = 19