Answer:
D
Step-by-step explanation:
so total travel by x bikers = 50 multiplied by x = 50x
According to the question
  50x = 560
dividing 560 miles by 50 miles per biker give ya 11.2 or approximately 12 bikers. 
 
        
             
        
        
        
75*.2=15
you would save $15
hope that helps
        
             
        
        
        
Answer:
(B) 0.74 + or - 2.797 × 0.22/√25
Step-by-step explanation:
Confidence Interval = mean + or - t × sd/√n
mean = 0.74 hours
sd = 0.22 hours
n = 25
degree of freedom = n - 1 = 25 - 1 = 24
Confidence level = 99%
t-value corresponding to 24 degrees of freedom and 99% confidence level is 2.797
Confidence Interval = 0.74 + or - 2.797 × 0.22/√25