There are approximately 4 weeks in a month.

The shop owner added 3 bikes every week for 4 weeks for a total addition of 3*4 = <<3*4=12>>12 bikes

The shop owner now has the original number of bikes + <<12=12>>12 bikes

She sold 18 bikes within the same time frame

She now has a total of 45 bikes which is: the original number of bikes + 12 - 18 = <<45=45>>45 bikes

The original number of bikes = 45-12+18 = <<45-12+18=51>>51 bikes

# Answer

51
<|im_start|>system
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<|im_start|>user
A bicycle shop owner adds 3 bikes to her stock every week. After 1 month, she had sold 18 bikes but still had 45 bikes in stock. How many bikes did she have originally?
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51
A bicycle shop owner adds 3 bikes to her stock every week. After 1 month, she had sold 18 bikes but still had 45 bikes in stock. How many bikes did she have originally?
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