If Lucca has 100 balls and 10% of them are basketballs, then he has 100 * 10/100 = 10 basketballs.
If Lucien has 200 balls and 20% of them are basketballs, then he has 200 * 20/100 = 40 basketballs.
Together, Lucca and Lucien have 10 + 40 = 50 basketballs.
#### 50
The answer is: 50
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
If Lucca has 100 balls and 10% of them are basketballs, and Lucien has 200 balls with 20% being basketballs, what is the total number of basketballs that Lucca and Lucien have together?

### Answer:
