1. **State the problem:**
We have an arithmetic progression (AP) where the first term $a_1 = 300$ metres and the common difference $d = 50$ metres. The total number of rounds is 10.
2. **Find the 4th, 5th, and 6th terms of the AP:**
The formula for the $n$th term of an AP is:
$$a_n = a_1 + (n-1)d$$
Calculate each term:
- $a_4 = 300 + (4-1) \times 50 = 300 + 150 = 450$
- $a_5 = 300 + (5-1) \times 50 = 300 + 200 = 500$
- $a_6 = 300 + (6-1) \times 50 = 300 + 250 = 550$
3. **Determine the distance of the 8th round:**
Using the same formula:
$$a_8 = 300 + (8-1) \times 50 = 300 + 350 = 650$$
4. **Find the total distance run after completing all 10 rounds:**
The sum of the first $n$ terms of an AP is:
$$S_n = \frac{n}{2} (2a_1 + (n-1)d)$$
Calculate $S_{10}$:
$$S_{10} = \frac{10}{2} (2 \times 300 + (10-1) \times 50) = 5 (600 + 450) = 5 \times 1050 = 5250$$
5. **Find the total distance run if only the first 6 rounds are completed:**
Calculate $S_6$:
$$S_6 = \frac{6}{2} (2 \times 300 + (6-1) \times 50) = 3 (600 + 250) = 3 \times 850 = 2550$$
**Final answers:**
- Fourth term: $450$ metres
- Fifth term: $500$ metres
- Sixth term: $550$ metres
- Distance of 8th round: $650$ metres
- Total distance after 10 rounds: $5250$ metres
- Total distance after 6 rounds: $2550$ metres
Arithmetic Progression D0Aa17
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