Answer:
4.5 meters
Explanation:
If the pins were placed 30 cm apart, and there were a total of 15 pins, then the length of the string is 30 cm * 15 pins = <<30*15=450>>450 cm.
To convert this length to meters, we divide the number of centimeters by 100: 450 cm / 100 = 4.5 meters.
Therefore, the length of the string is 4.5 meters.