Final answer:
George won £838, and when rounded to the nearest £100, the amount is £800 (option a).
Step-by-step explanation:
When rounding to the nearest £100, we look at the digit in the tens place of the amount in question to decide whether to round up or down. If the digit in the tens place is 5 or more, we round up, and if it is 4 or less, we round down. In George's case, he won £838. The tens digit here is 3, which is less than 5. Therefore, we round down to the nearest hundred.
So, the amount rounded to the nearest £100 would be £800. The correct answer to this question is option a: £800.