Pricing strategy (discounts, coupons) in LLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to apply a fixed discount to the original price.

LLD

final_price = original_price - [1]

Drag options to blanks, or click blank then click option'

Adiscount_amount

Bdiscount_rate

Ccoupon_code

Dtax_amount

Attempts:

3 left

💡 Hint

Common Mistakes

Using discount_rate instead of discount_amount

Subtracting tax_amount instead of discount

The fixed discount amount should be subtracted from the original price to get the final price.

2fill in blank

medium

Complete the code to calculate the discount amount from a percentage rate.

LLD

discount_amount = original_price * [1]

Drag options to blanks, or click blank then click option'

Afinal_price

Bcoupon_code

Cdiscount_rate

Dtax_rate

Attempts:

3 left

💡 Hint

Common Mistakes

Using coupon_code instead of discount_rate

Multiplying by tax_rate by mistake

The discount amount is calculated by multiplying the original price by the discount rate (percentage as a decimal).

3fill in blank

hard

Fix the error in the code to apply a coupon discount only if the coupon is valid.

LLD

if coupon.is_valid():
    final_price = original_price - [1]

Drag options to blanks, or click blank then click option'

Acoupon.discount_amount

Btax_amount

Cdiscount_rate

Dcoupon_code

Attempts:

3 left

💡 Hint

Common Mistakes

Using coupon_code string instead of discount_amount

Subtracting tax_amount by mistake

Use the discount amount associated with the coupon object to subtract from the original price.

4fill in blank

hard

Fill both blanks to calculate the final price after applying a percentage discount and adding tax.

LLD

discount_amount = original_price * [1]
final_price = (original_price - discount_amount) * (1 + [2])

Drag options to blanks, or click blank then click option'

Adiscount_rate

Btax_rate

Cdiscount_amount

Dcoupon_code

Attempts:

3 left

💡 Hint

Common Mistakes

Using coupon_code instead of discount_rate

Adding tax before subtracting discount

First calculate discount_amount using discount_rate, then add tax by multiplying with (1 + tax_rate).

5fill in blank

hard

Fill all three blanks to create a dictionary of coupons with their discount rates, filtering only those above 10%.

LLD

coupons = {code: [1] for code, [2] in all_coupons.items() if [3] > 0.1}

Drag options to blanks, or click blank then click option'

Adiscount_rate

Dcoupon_code

Attempts:

3 left

💡 Hint

Common Mistakes

Using coupon_code as value

Filtering by code instead of discount_rate

Use discount_rate as the value, iterate over code and discount_rate, and filter where discount_rate is greater than 10%.

Practice

1. What is the primary purpose of implementing discounts and coupons in a pricing strategy?

easy

A. To reduce product quality

B. To increase the base price of products

C. To make the checkout process slower

D. To attract more customers and increase sales volume

Solution

1. Step 1: Understand the role of discounts and coupons

   Discounts and coupons are marketing tools used to lower prices temporarily.

2. Step 2: Identify the business goal

   Lower prices attract more customers, which can increase sales volume and customer loyalty.

3. Final Answer:

   To attract more customers and increase sales volume -> Option D

4. Quick Check:

   Discounts and coupons = attract customers [OK]

Hint: Discounts attract customers by lowering prices [OK]

Common Mistakes:

• Thinking discounts increase prices
• Confusing discounts with product quality
• Assuming coupons slow checkout

2. Which of the following is the correct way to represent a discount of 20% in a pricing system?

easy

A. discount = 20

B. discount = 2

C. discount = 0.2

D. discount = 200

Solution

1. Step 1: Understand percentage representation in code

   Percentages are usually represented as decimals for calculations, so 20% is 0.2.

2. Step 2: Check each option

   discount = 0.2 uses 0.2 which is correct; others are incorrect as they represent wrong values.

3. Final Answer:

   discount = 0.2 -> Option C

4. Quick Check:

   20% = 0.2 decimal [OK]

Hint: Use decimal for percentage (20% = 0.2) [OK]

Common Mistakes:

• Using whole number 20 instead of decimal
• Confusing 2 or 200 as percentage
• Not converting percentage to decimal

3. Consider this code snippet for applying a coupon discount:

price = 100
coupon_discount = 15  # fixed amount
final_price = price - coupon_discount
print(final_price)

What will be the output?

medium

A. 85

B. 15

C. 100

D. 115

Solution

1. Step 1: Understand the variables

   Price is 100, coupon_discount is 15 fixed amount.

2. Step 2: Calculate final price

   final_price = 100 - 15 = 85.

3. Final Answer:

   85 -> Option A

4. Quick Check:

   100 - 15 = 85 [OK]

Hint: Subtract fixed coupon value from price [OK]

Common Mistakes:

• Confusing discount as percentage
• Adding instead of subtracting discount
• Printing coupon_discount instead of final price

4. In the following code, what is the error that prevents correct discount application?

price = 200
discount = 20  # intended as 20%
final_price = price - discount
print(final_price)

medium

A. Price should be multiplied by discount directly

B. Discount should be converted to decimal before calculation

C. Discount should be added to price

D. No error, code is correct

Solution

1. Step 1: Identify discount representation

   Discount is 20 but intended as 20%, so it should be 0.2 in decimal.

2. Step 2: Correct calculation method

   final_price should be price - (price * discount_decimal), not price - discount integer.

3. Final Answer:

   Discount should be converted to decimal before calculation -> Option B

4. Quick Check:

   20% = 0.2 decimal needed [OK]

Hint: Convert percentage to decimal before subtracting [OK]

Common Mistakes:

• Subtracting integer discount directly
• Adding discount instead of subtracting
• Ignoring percentage to decimal conversion

5. You are designing a system that applies multiple discounts: a 10% seasonal discount and a $5 coupon. If the original price is $50, what is the correct final price after applying both discounts sequentially?

hard

A. $40.5

B. $45

C. $40

D. $42

Solution

1. Step 1: Apply the $5 coupon discount first

   $50 - $5 = $45.

2. Step 2: Apply the 10% seasonal discount

   $45 * 0.9 = $40.5.

3. Step 3: Sequential discounts

   Coupon before percentage discount yields $40.5.

4. Final Answer:

   $40.5 -> Option A

5. Quick Check:

   Coupon then percentage = 40.5 [OK]

Hint: Order of discounts affects final price [OK]

Common Mistakes:

• Applying discounts in wrong order
• Adding discounts instead of subtracting
• Ignoring percentage vs fixed discount difference