Final answer:
The expected value of buying the maintenance contract is -$51.80, indicating that, on average, buying the contract would result in a loss.
Step-by-step explanation:
To calculate the expected value of buying the maintenance contract, we need to consider the cost of repairs with and without the contract. Without the contract, there is a 12% chance of needing a $140 repair, so the expected cost without the contract is 12% * $140 = $16.80. With the contract, all repairs are free, so the expected cost with the contract is $0.
The cost of the maintenance contract is $35. Therefore, the expected value of buying the maintenance contract is:
Expected value = $0 (cost with contract) - $16.80 (cost without contract) - $35 (cost of contract) = -$51.80
Since the expected value is negative, it means that, on average, buying the maintenance contract would result in a loss. Therefore, it may not be a wise decision to buy the maintenance contract.