you can use a calculator if you want. No links please help this is very important i will give you brain thing if its correct

Answer:
The tip would be $6.36
Explanation:
If the bill was $42.40, and you wanted to leave 15% tip
[tex]42.40 * 0.15[/tex]
0.15 is the same as 15% and you multiple it by the amount to get your tip