Yield farming concepts in Blockchain / Solidity - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Yield Farming Rewards

In yield farming, users provide liquidity to a pool and earn rewards. Which of the following best describes how rewards are typically calculated?

A Rewards are randomly assigned to users each day.

B Rewards are proportional to the amount of liquidity a user provides relative to the total pool.

C Rewards depend only on the time a user has held tokens, not the amount provided.

D Rewards are fixed and distributed equally regardless of the amount provided.

💡 Hint

Think about fairness in sharing rewards based on contribution size.

In yield farming, rewards are usually proportional to the liquidity a user provides compared to the total pool. This ensures users who contribute more get more rewards.

❓ Predict Output

intermediate

Calculate User Share in a Liquidity Pool

Given the following Python code that calculates a user's share percentage in a liquidity pool, what is the output?

Blockchain / Solidity

total_liquidity = 1000
user_liquidity = 250
user_share = (user_liquidity / total_liquidity) * 100
print(f"User share: {user_share:.1f}%")

A User share: 250.0%

B User share: 2.5%

C User share: 0.25%

D User share: 25.0%

💡 Hint

Divide user liquidity by total liquidity and multiply by 100 to get percentage.

The user provides 250 out of 1000 total liquidity, so the share is (250/1000)*100 = 25.0%.

❓ Predict Output

advanced

Yield Farming Reward Calculation with Variable Rates

Consider this Python function that calculates rewards based on liquidity and a variable reward rate. What is the output when calling calculate_rewards(500, 0.05)?

Blockchain / Solidity

def calculate_rewards(liquidity, reward_rate):
    return liquidity * reward_rate

print(calculate_rewards(500, 0.05))

A 500.05

B 10.0

C 25.0

D 0.025

💡 Hint

Multiply liquidity by reward rate to get rewards.

500 * 0.05 equals 25.0, which is the reward amount.

🔧 Debug

advanced

Identify the Error in Reward Distribution Code

What error will this Python code produce when run?

Blockchain / Solidity

rate = 0.1
rewards = {user: liquidity * rate for user, liquidity in [('Alice', 100), ('Bob', 200)]}
print(rewards)

A {'Alice': 10.0, 'Bob': 20.0}

B TypeError due to wrong multiplication

C NameError because 'rate' is used before assignment

D SyntaxError in dictionary comprehension

💡 Hint

Check the order of variable definitions and usage.

The variable 'rate' is used inside the dictionary comprehension before it is defined, causing a NameError.

🧠 Conceptual

expert

Risks in Yield Farming Strategies

Which of the following is the most significant risk unique to yield farming compared to traditional savings?

A Smart contract vulnerabilities causing loss of funds

B Inflation risk reducing the value of rewards

C Interest rate changes by central banks

D Bank insolvency leading to loss of deposits

💡 Hint

Think about what can go wrong specifically in blockchain-based yield farming.

Yield farming involves smart contracts which can have bugs or be exploited, risking users' funds. This risk is unique compared to traditional savings.

Practice

1. What is the main purpose of yield farming in blockchain?

easy

A. To trade cryptocurrencies on exchanges

B. To earn rewards by staking cryptocurrency in pools

C. To mine new cryptocurrency coins

D. To create new blockchain networks

Solution

1. Step 1: Understand yield farming basics

   Yield farming involves staking crypto assets to earn rewards.

2. Step 2: Compare options to yield farming

   Mining, trading, and creating blockchains are different activities.

3. Final Answer:

   To earn rewards by staking cryptocurrency in pools -> Option B

4. Quick Check:

   Yield farming = earning rewards by staking [OK]

Hint: Yield farming means staking crypto to earn rewards [OK]

Common Mistakes:

• Confusing yield farming with mining
• Thinking yield farming is trading
• Believing yield farming creates new blockchains

2. Which of the following is the correct way to describe a yield farming pool?

easy

A. A software to trade cryptocurrencies instantly

B. A wallet to store cryptocurrencies securely

C. A blockchain that creates new tokens automatically

D. A place where users stake crypto to earn rewards

Solution

1. Step 1: Define a yield farming pool

   A pool is where users stake crypto to earn rewards.

2. Step 2: Eliminate unrelated options

   Wallets store crypto, blockchains create tokens, and software trades crypto.

3. Final Answer:

   A place where users stake crypto to earn rewards -> Option D

4. Quick Check:

   Pool = staking place for rewards [OK]

Hint: Pools are for staking crypto to earn rewards [OK]

Common Mistakes:

• Mixing pools with wallets
• Thinking pools create tokens
• Confusing pools with trading software

3. Consider this simplified code snippet for calculating yield farming rewards:

def calculate_rewards(staked_amount, reward_rate):
    return staked_amount * reward_rate

print(calculate_rewards(1000, 0.05))

What is the output of this code?

medium

A. 50.0

B. 5

C. 1000

D. 0.05

Solution

1. Step 1: Understand the function calculation

   The function multiplies staked_amount (1000) by reward_rate (0.05).

2. Step 2: Calculate the multiplication

   1000 * 0.05 = 50.0

3. Final Answer:

   50.0 -> Option A

4. Quick Check:

   1000 * 0.05 = 50 [OK]

Hint: Multiply staked amount by reward rate [OK]

Common Mistakes:

• Confusing multiplication with addition
• Using reward rate as output directly
• Mixing up staked amount and reward rate

4. Find the error in this yield farming reward calculation code:

def calculate_rewards(staked_amount, reward_rate):
    rewards = staked_amount + reward_rate
    return rewards

print(calculate_rewards(1000, 0.05))

medium

A. Incorrect function name

B. Missing return statement

C. Using addition instead of multiplication for rewards

D. Wrong print syntax

Solution

1. Step 1: Review the reward calculation logic

   The code adds staked_amount and reward_rate instead of multiplying.

2. Step 2: Understand correct reward formula

   Rewards should be staked_amount * reward_rate, not addition.

3. Final Answer:

   Using addition instead of multiplication for rewards -> Option C

4. Quick Check:

   Rewards = stake * rate, not stake + rate [OK]

Hint: Rewards = stake times rate, not plus rate [OK]

Common Mistakes:

• Adding instead of multiplying rewards
• Forgetting to return value
• Misnaming functions
• Incorrect print usage

5. You want to calculate total rewards from multiple pools with different stakes and rates:

pools = {"PoolA": (1000, 0.05), "PoolB": (2000, 0.03), "PoolC": (1500, 0.04)}
total_rewards = sum(stake * rate for stake, rate in pools.values())
print(total_rewards)

What is the output of this code?

hard

A. 170.0

B. 0.12

C. 4500

D. SyntaxError

Solution

1. Step 1: Calculate rewards for each pool

   PoolA: 1000*0.05=50, PoolB: 2000*0.03=60, PoolC: 1500*0.04=60

2. Step 2: Sum all rewards

   Total = 50 + 60 + 60 = 170

3. Step 3: Verify code output

   The code prints the sum of rewards, which is 170.0 (float)

4. Final Answer:

   170.0 -> Option A

5. Quick Check:

   Sum of all pool rewards = 170.0 [OK]

Hint: Sum stake * rate for each pool to get total rewards [OK]

Common Mistakes:

• Adding rates instead of multiplying
• Forgetting to sum all pools
• Expecting integer output instead of float
• Misreading dictionary values