Problem: How does the sentence end?

The students took a longer time calculating the physics problem than the engineering problem since the 
Answer: physics problem was rather complex.

Problem: How does the sentence end?

The GM decided to promote Joseph instead of Derrick because 
Answer: Joseph is a very capable salesperson.

Problem: How does the sentence end?

The payment on the car was less than the payment on the motorbike because the 
Answer: motorbike was a nicer vehicle.

Problem: How does the sentence end?

Erin was better at driving than Kayla although 
Answer:
Kayla had taken a driver's safety class at school.