Answer: mess
Step-by-step explanation:
 
        
                    
             
        
        
        
They both get their cars washed on every 60th day.
You can solve this equation by finding the lcm (least common multiple):
15 30 45 60 75 90 105
20 40 60 80 100
The lowest common multiple is 60 as it is the first multiple the two have in common. 
So, in sixty days, they’ll both get their car washed again
        
                    
             
        
        
        
Step-by-step explanation:
Given that the mean of the numbers is 12

so here 
let's that one as x and another one as 2x since it is given that one is twice the other
Therefore we get

Given mean = 12




Hence it's 11 and 22
 
        
             
        
        
        
1 foot = 12 inches
12 * 5 = 60 and 8 * 12 = 96
Therefore, 60 inches is a shorter length than 8 feet.