Week 1. 100 km
Week 2. 130 km
Week 3. 160 km
Week 4. 190 km
Week 5. 220 km
Week 6. 250 km
Week 7. 280 km
Week 8. 310 km
Now it depends what do you exactly mean by "car is driven". If it's travelling 30 km more every week, then we just have to sum the numbers up: 100 + 130 + 160 + 190 + 220 + 250 + 280 + 310 = 1640 km.
But if it had done 100 km before and it just travels 30 km every week, then we have to count it like this: 100 + 30 * 7 = 100 + 210 = 310 km.
