Question 1209515
Here's how to solve this problem:

1. **Express the ratios as fractions:**

* A : B : C = 1 : 3  can be written as A/B = 1/3
* C : (A + B) = 3 : 4 can be written as C/(A + B) = 3/4

2. **Express B in terms of A:**

From A/B = 1/3, we get B = 3A

3. **Substitute B in the second ratio:**

C / (A + 3A) = 3/4
C / 4A = 3/4

4. **Express C in terms of A:**

C = (3/4) * 4A
C = 3A

5. **Use the information about the difference between A and B:**

B = A + 50
Since B = 3A, we can write:
3A = A + 50
2A = 50
A = 25

6. **Find the number of oranges in C:**

C = 3A
C = 3 * 25
C = 75

Therefore, there were 75 oranges in basket C.