Final answer:
Kimberly will have to make a total of 7 trips to walk a total of 49 kilometers.
Step-by-step explanation:
To find out how many trips Kimberly will have to make to walk a total of 49 kilometers, we need to subtract the distance she has already walked (42 kilometers) from the total distance she wants to walk (49 kilometers). This gives us the additional distance she needs to walk, which is 49 km - 42 km = 7 kilometers.
Since Kimberly plans to walk 1 kilometer during each trip to school, we can divide the additional distance she needs to walk by 1 kilometer to find out how many trips she will have to make. So, 7 kilometers ÷ 1 kilometer = 7 trips.
Therefore, Kimberly will have to make a total of 7 trips to walk a total of 49 kilometers.