MBE Rules · Contracts
Mistake — unilateral
The rule
A unilateral mistake makes a contract voidable only if (1) the elements of mutual mistake are met from the mistaken party's side AND (2) either enforcement would be unconscionable OR the other party had reason to know of, or caused, the mistake.
In plain English
If only one party is mistaken about a contract term, the contract can be canceled if the mistake is really unfair or the other party knew or caused the mistake.
Worked example
The buyer mistakenly thinks a painting is an original due to a misleading label placed by the seller. The buyer can void the contract because the seller caused the mistake.
Memory hook
Unilateral = one-sided slip-up. Voidable if mutual mistake + unfair enforcement or sneaky other party.
The trap
Students think: any mistake voids contract. Wrong, because unilateral mistakes require more. The actual test is mutual mistake elements + unfairness or knowledge.
How examiners test it
The MBE loves: one party miscalculates bid, other party stays silent. Question: voidable? Trap: assuming any mistake suffices. Must show unfairness or other party's knowledge.
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