Complete question is in comment section :
Answer:
68%
Step-by-step explanation:
Mean = 25
Standard deviation = 5
The percentage of trees between 20 and 30
20 trees = 1 standard deviation below the mean ; mean - 1(standard deviation)
25 - 5 = 20
30 trees = 1 standard deviation above the mean ;
Mean + 1(standard deviation) ;
25 + 5 = 30
This means, 20 and 30 lies ±1 standard deviation from the mean which according to the empirical rule is 68%
According to the empirical rule :
