The mass of a cylinder filled with gas is 30 kg 250 g and the mass of the empty cylinder is 14 kg 480 g. How much is the mass of the gas contained in it ?

Answer

To find the mass of the gas contained in the cylinder, we will follow these steps:

### Step 1: Write down the given information
- The mass of the filled cylinder: 30 kg 250 g
- The mass of the empty cylinder: 14 kg 480 g

### Step 2: Convert the masses to a uniform unit (grams)
1. **Convert the mass of the filled cylinder:**
- 30 kg = 30 × 1000 g = 30,000 g
- Therefore, the mass of the filled cylinder = 30,000 g + 250 g = 30,250 g

2. **Convert the mass of the empty cylinder:**
- 14 kg = 14 × 1000 g = 14,000 g
- Therefore, the mass of the empty cylinder = 14,000 g + 480 g = 14,480 g

### Step 3: Calculate the mass of the gas
- To find the mass of the gas, subtract the mass of the empty cylinder from the mass of the filled cylinder:

\[ \text{Mass of gas} = \text{Mass of filled cylinder} - \text{Mass of empty cylinder} \]

\[ \text{Mass of gas} = 30,250 g - 14,480 g \]

### Step 4: Perform the subtraction
- Align the numbers for subtraction:

```
30250
- 14480
```

- Start subtracting from the rightmost digit:
- 0 - 0 = 0
- 5 - 8: Cannot subtract, so we borrow 1 from the next column (making it 15 - 8 = 7).
- 4 (after borrowing) becomes 3. So, 3 - 4: Cannot subtract, borrow again (making it 13 - 4 = 9).
- 2 - 4: Cannot subtract, borrow again (making it 12 - 4 = 8).
- 2 - 1 = 1.

So, the result of the subtraction is:

\[ \text{Mass of gas} = 15,770 g \]

### Step 5: Convert the mass of the gas back to kg and g
- Since 1 kg = 1000 g:
- 15,770 g = 15 kg and 770 g.

### Final Answer:
The mass of the gas contained in the cylinder is **15 kg 770 g**.

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