One pizza costs twice as much as the burger, which means 9 * 2 = $<<9*2=18>>18.

Three burgers would cost 9 * 3 = $<<9*3=27>>27.

So one pizza and three burgers would cost in total 18 + 27 = $<<18+27=45>>45.

# Answer

45
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
In a restaurant, a burger costs $9, and a pizza twice as much. How much would cost one pizza and three burgers?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
45
In a restaurant, a burger costs $9, and a pizza twice as much. How much would cost one pizza and three burgers?
train