Only people who are maths champions can solve this brainteaser in 30 seconds

Brits are scratching their heads at this deceptively difficult maths question that needs to be solved in just 30 seconds or less. You’ll need to be a real boffin to be able to crack this oneBrits are scratching their heads at this deceptively difficult maths question that needs to be solved in just 30 seconds or less. You’ll need to be a real boffin to be able to crack this one