Give the step-by-step reasoning process and then the final answer. Christina walks 7km to school every day from Monday to Friday. She returns home covering the same distance. Last Friday her mother asked her to pass by her friend, which is another 2km away from the school in the opposite distance from home. How many kilometers did Christina cover that week?
One trip to school is 2 * 7 km = 14km. In one week, Christina walks 14 km / day * 5 days / week = 70km to school. The extra trip to her mum's friend added 2 km * 2 = 4km to her travel distance. Her total distance was thus 70 km + 4 km = 74 km.
The final answer: 74.