The problem states that a trader buys 12 durians, paying with 3 bills of Rp100,000 each (Rp300,000 in total), and receives Rp30,000 in change. We need to determine how much the trader should pay if they only buy 8 durians instead of 12.

Step 1: Calculate the price of 12 durians.

The total money paid is Rp300,000, and the change received is Rp30,000. The actual amount spent on 12 durians is: $\text{Total spent} = Rp300,000 - Rp30,000 = Rp270,000$

Step 2: Determine the price per durian.

To find the cost of one durian, we divide the total spent by the number of durians: $\text{Price per durian} = \frac{Rp270,000}{12} = Rp22,500$

Step 3: Calculate the cost for 8 durians.

Now that we know each durian costs Rp22,500, the cost for 8 durians is: $\text{Cost for 8 durians} = 8 \times Rp22,500 = Rp180,000$

Answer:

The trader would need to pay Rp180,000 for 8 durians. The correct answer is D. Rp180,000.

Would you like further details or have any questions?

Here are five related questions for further practice:

1. If the trader bought 10 durians instead, how much would they pay?
2. What would the price per durian be if the total cost of 12 durians was Rp300,000 without any change?
3. If the price of one durian increased by 10%, how much would 8 durians cost?
4. How much would the trader save by buying 6 durians instead of 8?
5. If the trader received a 5% discount for buying 8 durians, how much would they pay?

Tip: When working with price-per-item problems, always break down the total cost into manageable parts like price per unit.