Final answer:
The cost per battery, when rounding to the nearest penny, would be £0.50, calculated by dividing the total cost (£3.99) by the number of batteries (8).
Step-by-step explanation:
To calculate how much each battery costs, we can divide the total cost of the pack by the number of batteries in the pack. If a pack of 8 batteries costs £3.99, we do the following calculation:
£3.99 ÷ 8 = £0.49875 per battery
Since we need to round to the nearest penny, the cost per battery would be £0.50.