Answer:
 Total bill including the tip = $156.86 .
Explanation:
Given:Bill at a restaurant came to $136.40 the patrons decide to leave a 15% tip .
To find: What is the total bill including the tip.
Solution: we have given that 
A restaurant bill came = $136.40 .
Tip percentage = 15% of bill 
Tip cost = 15% of $136.40 .
Tip cost = $20.46 .
 So, total bill including the tip = $136.40 + tip cost 
 = $136.40 + $20.46
 = $156.86 .
Therefore , Total bill including the tip = $156.86 .