To solve the problem regarding Pak Jaya's and his wife's ages at the time of their marriage, we can proceed as follows:

Given:

• Pak Jaya's age at marriage = 25 years
• The ratio of Pak Jaya's age to his wife's age at the time of marriage = 5:4

Let's solve it:

Let the wife's age at the time of marriage be $x$ years.

According to the ratio, the ages are related by: $\frac{\text{Pak Jaya's age}}{\text{Wife's age}} = \frac{5}{4}$

This implies: $\frac{25}{x} = \frac{5}{4}$

To find $x$, cross-multiply: $25 \times 4 = 5 \times x$

Simplifying: $100 = 5x$

Dividing both sides by 5: $x = \frac{100}{5} = 20 \text{ years}$

Answer:

The age of Pak Jaya's wife at the time of marriage is 20 years.

The correct answer is B. 20 years.

Would you like more details or have any other questions? Here are some related questions:

1. What is the method for solving ratio problems involving ages?
2. How would the solution change if Pak Jaya's age were different?
3. What if the ratio of their ages was different, such as 6:5?
4. Can we apply this ratio concept to other types of problems?
5. How would you solve a problem where both current and past ages are given with a ratio?

Tip: When dealing with ratios, cross-multiplication is a powerful tool to solve for the unknown variable effectively.