They ate a total of 4 x 2 = <<4*2=8>>8 pieces of candy after the event.

So, Travis and his brother have 68 - 8 = <<68-8=60>>60 pieces of candy left.

# Answer

60
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Travis and his brother joined a trick-or-treat event. They collected 68 pieces of candy altogether. Each of them ate 4 pieces of candy after the event. How many pieces of candy were left?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
60
Travis and his brother joined a trick-or-treat event. They collected 68 pieces of candy altogether. Each of them ate 4 pieces of candy after the event. How many pieces of candy were left?
train