V = 7.67 (aproximately) mph
1) Gathering the data
Before the storm
50 miles
3 hour drive
After the storm
68 miles
Speed: 9 mph - x
2) Let's find the speed of Nancy before the storm:
Since in the storm the Speed was 9 mph less than 16.67 mph we have:
16.67 -9 =7.67 mph
3) Hence, her speed driving at the storm was 7.67 mph