Explain simply why 225 is the correct answer to: Eliza buys 200 ornamental rings to sell in their local shop, twice the number of the remaining stock. After selling 3/4 of the total stock, her mother buys 300 more ornamental rings, and after three days, sells 150. What's the total number of ornamental rings remaining in the store?. Explanation:
If Eliza restocked twice the original number of ornamental rings, the number was 200 / 2 = 100 rings. The total number of ornamental rings in stock is now 200 + 100 = 300 rings. When she sells 3 / 4 of the stock, the total number of rings sold is 3 / 4 * 300 = 225 rings. The remaining stock is 300 - 225 = 75 rings. When her mother buys 300 more rings, the stock is boosted to 75 + 300 = 375 rings. She then sells out 150, reducing the stock to 375 - 150 = 225 rings.