To find the total amount Brian paid, we need to calculate the tip and then add it to the cost of the food.
1. First, we determine the cost of the food, which is [tex]$42.
2. Next, we calculate the tip. A 15% tip means we multiply the cost of the food by 15% (or 0.15):
\[ \text{Tip amount} = 42 \times 0.15 = 6.3 \]
3. The final step is to add the tip amount to the original food cost:
\[ \text{Total amount} = 42 + 6.3 = 48.3 \]
Therefore, the total amount Brian paid is \( \text{\$[/tex]}48.30 \).
