1. The problem states that John and Mary share a sum of money in the ratio 4:1. 2. John received 600 dollars, and we need to find Mary's share. 3. Let the total parts be $4 + 1 = 5$ parts. 4. John's share corresponds to 4 parts, which equals 600 dollars. 5. To find the value of one part, divide John's amount by 4: $$\text{One part} = \frac{600}{4} = 150$$ 6. Mary's share corresponds to 1 part, so Mary's share is: $$150$$ 7. Therefore, Mary's share is 150 dollars.