Answer:
We can use the proportion method to solve this problem.
Let's define the rate of dough preparation as the amount of dough Lia can prepare per hour. We can write:
rate = amount of dough / time
We are given that Lia prepared 35 kg of dough in 7 hours. We can use this information to find her rate of dough preparation:
rate = 35 kg / 7 hours = 5 kg/hour
Now we can use this rate to find how much dough Lia will prepare if she works for 9 hours:
amount of dough = rate x time
amount of dough = 5 kg/hour x 9 hours = 45 kg
Therefore, if Lia works for 9 hours, she will prepare 45 kilograms of dough.