Let's break down the problem:

Danis buys two pairs of pants and a shirt. The store provides discounts for both the pants and the shirt.

1. Price of Pants: Rp 150,000 with an 80% discount.

   • Discount on pants = 80% of Rp 150,000 = $0.80 \times 150,000 = 120,000$.
   • Therefore, the price Danis pays for each pair of pants = $150,000 - 120,000 = 30,000$.
   • Since Danis buys two pairs of pants, the total cost for pants is $30,000 \times 2 = 60,000$.

2. Price of the Shirt: Rp 120,000. The discount for the shirt is unknown, and we need to find it.

Danis pays with Rp 350,000 and receives Rp 36,000 as change. Therefore, the total amount Danis paid is:

$350,000 - 36,000 = 314,000$

Now, let's express the total payment as the sum of the cost for the pants and the discounted price for the shirt:

$\text{Total Payment} = \text{Cost of Pants} + \text{Discounted Price of the Shirt}$ $314,000 = 60,000 + \text{Discounted Price of the Shirt}$ $\text{Discounted Price of the Shirt} = 314,000 - 60,000 = 254,000$

This implies that Danis paid Rp 254,000 for the shirt after the discount.

Now, let's find the percentage discount on the shirt. The original price of the shirt is Rp 120,000, and the discounted price is Rp 254,000 - 60,000 = Rp 94,000.

Therefore, the discount is:

$\text{Discount} = \frac{120,000 - 94,000}{120,000} \times 100\% = \frac{26,000}{120,000} \times 100 = 21.67\%$

Thus, the discount percentage on the shirt is closest to 30%.

The answer is B. 30%.

Would you like more details, or do you have any questions?

Here are 5 related questions to expand on this concept:

1. How would the total change if Danis bought only one pair of pants?
2. What is the formula to calculate percentage discounts?
3. How would the calculation change if the pants had a different discount percentage?
4. What if Danis had been given Rp 50,000 in change? How would that affect the shirt discount?
5. How would you calculate the total cost if taxes were added after discounts?

Tip: Always subtract the discount from the original price before multiplying it with the quantity!