Answer:
The mean is 66.667 ( approx )
Step-by-step explanation:
Let x be the sum of Tony's group and y be the sum of Alice's group,
We know that,
[tex]Mean = \frac{\text{Total sum of observations}}{\text{Number of observations}}[/tex]
According to the question,
In Tony's group,
Students = 20,
Mean = 60,
[tex]\implies \frac{x}{20}=60\implies x = 1200[/tex]
In Alice's group,
Students = 10,
Mean = 80,
[tex]\implies \frac{y}{10}=80\implies y = 800[/tex]
Thus, the total sum of combined group of 30 students = 1200 + 800 = 2000,
Hence, the mean of the combined group = [tex]\frac{2000}{30}[/tex]
[tex]\approx 66.667[/tex]
