Final answer:
To find the ages of Rona and Diana in 12 years, we can set up an equation based on the information given. After solving the equation, we find that Diana's age in 12 years will be 59, and Rona's age in 12 years will be 54.
Step-by-step explanation:
To solve this problem, we need to translate the information given into equations.
Let's assume Diana's current age is D.
According to the problem, Rona is 5 years younger than Diana today, so Rona's current age is D-5.
The sum of their ages is 89, so we can write the equation D + (D-5) = 89.
Simplifying this equation, we get 2D = 94, and dividing both sides by 2, we find D = 47.
Therefore, Diana's age in 12 years will be 47 + 12 = 59, and Rona's age in 12 years will be (47-5) + 12 = 54.