<human>:  Bill starts on the 3rd floor. He rides the elevator up to the floor that's equal to 4 times his starting floor plus <human>: Continue.
<bot>: How many floors are in the building? ** First multiply Bill's starting floor number by 4: 3 * 4 = <<3*4=12>>12
How many floors are in the building? ** Then add six to find the ending floor Bill is on: 12 + 6 = <<12+6=18>>18
#### 18