To find the first person who will receive both a cookie and a drink, you can find the least common multiple (LCM) of 12 and 15, which represents the number of people who need to be in line for both events to coincide.
The LCM of 12 and 15 is 60. This means that every 60th person will receive both a cookie and a drink. Therefore, the first person to receive both a drink and a cookie will be the 60th person in line.