Detailed step-by-step solution:
Length of Gate 2 = 15 feet
Length of Gate 1 = 14 feet more than gate 2
= (15 + 14) feet = 29 feet
Length of Gate 1 is 6 feet shorter than Gate 3.
So, Gate 3 is 6 feet longer than Gate 1.
Length of Gate 3 = 29 + 6 = 35 feet
Therefore, the length of Gate 3 is 35 feet.