When the greatest common factor of two numbers is 1 or -1, the numbers are known as relatively prime. This means there are no numbers that can be factored out of both of the numbers, meaning if the numerator and denominator are relatively prime, they can not be simplified any further.
It would be an odd number of teams. What I did was add 43 and 34 together. Which gave me 77. So 77 people total wanted to race. There can only be 8 racers on each team. Each means to divide. So I divided 8 and 77. It gave me 9 with a remainder of 5. So there will e 9 teams and 5 racers left out. (: