Answer: Yes, she can drive round-trip to see her cousin on the free gas.
Explanation:
Given : Ms o'Malley cousin live 1,650 miles away. 
Ms o'Malley won a gift card for 100 gallons of gas.
I her car can travel 35 miles on each gallon.
Then, the total distance she can cover in 100 gallons of gas = 

Since 3500 miles > 1,650 miles 
It means she can drive round-trip to see her cousin on the free gas.
hence, the correct answer is "Yes".