3 years ago Lusia was 5 years old and Teresa was “a” years old. What will be the sum of their ages in “a” plus years?

If 3 years ago Lusia was 5 years old, that means Lusia's current age is 5 + 3 = 8 years old. Now, let's consider Teresa's age. If 3 years ago Teresa was "a" years old, her current age would be "a" + 3 years old. The sum of their ages in "a" plus years would be Lusia's current age (8) + Teresa's current age ("a" + 3). Therefore, the sum of their ages in "a" plus years is 8 + ("a" + 3) = 11 + "a".