Lydia is planning a road trip with her family and is trying to plan a route. She has 60 liters of fuel and she will use all of this during her trip. She isn't sure how much fuel she is going to use in the first third of the trip but she knows she will need a third of all of her fuel for the second third of the trip, and half this amount for the final third of the trip. How much fuel, in liters, can Lydia use in the first third of the trip? Let's think first. Chain of thought:
In the second third of the trip, Lydia is going to use 60 liters of fuel / 3 = 20 liters of fuel. In the final third of the trip, she needs half of this amount so she is going to be using 20 liters / 2 = 10 liters of fuel. So in the first third, Lydia used the remaining amount of fuel which is 60 total liters of fuel – 20 liters of fuel in the second third – 10 liters of fuel in the final third = 30 liters of fuel.
Therefore, the answer is 30.