Okay so we know that 3/5 of the conductors club went on the last camping trip. We also know that 3/5 of the club is equal to 39 people. All we have to do is find the last 2/5 and add it to our 3/5 to get the answer:
To find how much each 1/5 is, divide 39 by 3. This will give us 13. Then we multiply it by 5, because there are five parts. This gives us 65. So the answer is 65