It was revealed yesterday that the housemates would go up against each other in a male versus female challenge called 'Battle of the Brains'.
Answering several mathematical problems correctly, the boys were crowned 'Brainy Housemates', while the girls were branded 'Pea Brains'. In the second half of the challenge, the 'Brainy' group had to answer general knowledge questions, with each correct answer winning £50 towards the budget.
Aaron Allard-Morgan and Anton Murphy both answered two questions correctly, while Harry Blake, Tom O'Connell and Jay McKray added £50 each to the total. Jay had one correct answer disqualified after receiving help from the other housemates. Mark failed to answer either of his questions correctly.
However, the £400 budget was later cut to £350 when Big Brother punished Jay and Mark for throwing a bucket of 'Brain Sick' over each other. Aaron and Mark also tipped the liquid on the floor in the garden.
The 'Brainy Housemates' will complete the shopping list today.
The task will be shown during tonight's highlights show from 10pm on Channel 5.
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Watch the housemates enjoy their high-in-Omega 3 lunch below: