First find the total cost of the electricity: $4/watt * 300 watts = $<<4*300=1200>>1200

Then add the late fee: $1200 + $150 = $<<1200+150=1350>>1350

# Answer

1350
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Darla needs to pay $4/watt of electricity for 300 watts of electricity, plus a $150 late fee. How much does she pay in total?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
1350
Darla needs to pay $4/watt of electricity for 300 watts of electricity, plus a $150 late fee. How much does she pay in total?
train