Final answer:
The equation that models the situation is w + 6.5 = 20, where w represents the number of kilometers Ivania ran last week. Ivania ran 13.5 kilometers last week.
Step-by-step explanation:
To find the equation that models the situation, we need to represent the total distance Ivania ran this week and the distance she ran last week. Let's use the variable w to represent the number of kilometers she ran last week.
We know that Ivania ran a total of 20 km this week, which is 6.5 km farther than she ran last week. Since she ran w kilometers last week and 6.5 km farther this week, we can set up the equation: w + 6.5 = 20.
To solve for w, we can subtract 6.5 from both sides of the equation, giving us w = 20 - 6.5.
Therefore, Ivania ran 13.5 km last week.