You want to design a system that applies multiple discounts: a 10% seasonal discount and a $15 coupon. Which approach correctly calculates the final price for an item priced at $200?

hard📝 Trade-off Q8 of 15

LLD - Design — Online Shopping Cart

ASubtract $15 coupon first, then apply 10% discount

BApply 10% discount first, then subtract $15 coupon

CAdd 10% discount and $15 coupon together, then subtract from price

DApply only the larger discount between 10% and $15

Step-by-Step Solution

Solution:

Step 1: Understand discount order impact
Applying percentage discount first reduces price, then fixed coupon subtracts from that.
Step 2: Calculate final price stepwise
200 * 0.9 = 180; 180 - 15 = 165 final price.
Final Answer:
Apply 10% discount first, then subtract $15 coupon -> Option B
Quick Check:
Percentage then fixed coupon = correct order [OK]

Quick Trick: Apply percentage discounts before fixed amount coupons [OK]

Common Mistakes:

Reversing discount order
Adding discounts incorrectly

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You want to design a system that applies multiple discounts: a 10% seasonal discount and a $15 coupon. Which approach correctly calculates the final price for an item priced at $200?

Step 1: Understand discount order impact

Step 2: Calculate final price stepwise

Final Answer:

Quick Check:

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