The Jensen family traveled 210 miles on highways at a gas mileage of 35 miles per gallon, so they consumed 210 / 35 = 6 gallons of gas on highways.
They also traveled 54 miles on city streets at a gas mileage of 18 miles per gallon, so they consumed 54 / 18 = 3 gallons of gas on city streets.
In total, they consumed 6 + 3 = 9 gallons of gas for the entire trip.
#### 9
The answer is: 9
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
During a weekend road trip, the Jensen family traveled 210 miles on highways, where their car's gas mileage is 35 miles per gallon, and 54 miles on city streets, where their car's gas mileage is 18 miles per gallon. How many gallons of gas did they consume?

### Answer:
