1、A certain travel group is composed of 6 men and 9 women. It is known that the average age of the 6 men is 57 years old, and the average age of the 9 women is 52 years old. Then the average age of all members of this travel group is ( ) years old.
Answer: 54
Explanation: Average $(6 \times 57+9 \times 52) \div(6+9)=54$ (years)