Speed of the boat = u
speed of the current = v
in downstream,
u - v = 105/5
u - v = 21
in upstream
u + v = 105/7
u + v = 15
add both equations
2u = 36
u = 18
v = -3
so
speed of the boat = 18 km/h
speed of the current = 3 km/h
        
             
        
        
        
Answer:
second equation : 
( 20x² — 2xy — 42y² )
Step-by-step explanation:
expand the two brackets.
 
        
             
        
        
            
            
                Item 10 Find the median, first quartile, third quartile, and interquartile range of the data. 38,55,61,56,46,67,59,75,65,58 
                jok3333 [9.3K]             
         
        
I think the median is 58.5, the first quartile is 50.5, the third quartile is 66, and finally, the interquartile range is <span>12.75.</span>
        
             
        
        
        
Answer:
15
Step-by-step explanation:
15 minutes