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?
How many weeks are in a month? ** There are approximately 4 weeks in a month.
How many bikes did the shop owner add? ** The shop owner added 3 bikes every week for 4 weeks for a total addition of 3*4 = <<3*4=12>>12 bikes
How many bikes does the shop owner have now? ** The shop owner now has the original number of bikes + <<12=12>>12 bikes
How many bikes did the shop owner sell? ** She sold 18 bikes within the same time frame
How many bikes does the shop owner have now? ** She now has a total of 45 bikes which is: the original number of bikes + 12 - 18 = <<45=45>>45 bikes
How many bikes did the shop owner have originally? ** The original number of bikes = 45-12+18 = <<45-12+18=51>>51 bikes
#### 51