Final answer:
The mountain bike costs $267.75 at 4:40 a.m. after a 30% discount followed by a 10% discount on the already reduced price, calculated consecutively from the original price of $425.
Step-by-step explanation:
The question involves calculating the final price of a mountain bike after consecutive discounts are applied. To find the cost of the bike at 4:40 a.m., we initially applied a 30% discount to the regular price of $425. Calculating 30% of $425 gives us 0.30 × $425 = $127.50. Subtracting this from the original price, we get $425 - $127.50 = $297.50, which is the price after the first discount.
Next, an additional 10% discount is applied to the discounted price of $297.50. Calculating 10% of $297.50 is 0.10 × $297.50 = $29.75. Subtracting this additional discount from the discounted price, $297.50 - $29.75 gives us the final cost of the bike: $267.75.
Therefore, the mountain bike's cost at 4:40 a.m. after all discounts have been applied would be $267.75.