85 x 3 = 255
 first 2 test grades were 81 and 86: 
81 + 86 = 167
Need to find the 3rd to have exact average 85:
255 - 167 = 88
So her 3rd test needs to make 88 to make average of 85
Double check: 81 + 86 + 88 =  255 = 85 + 85 + 85
        
             
        
        
        
The sum of the magnitudes will be the magnitude of the sum when the vectors have the same direction.
        
             
        
        
        
Answer:

Step-by-step explanation:
Two angles are supplementary when they add up to 180°. 
So we know that: 

Supplanting we get:

We add up the X's. 


Then we send 64 to the other side adding: 



And then the 8 goes dividing: 


 
        
             
        
        
        
We are given with
dimensions of wheelbarrow = 2ft x 3ft x 1.5 ft
dimensions of truck = 11 ft x 8 ft x 6 ft
The volume of the wheelbarrow is 2(3)(1.5) = 9 ft3
The volume of the truck is 11(8)(6) = 528 ft3
70% of this is
528 ft3 (0.7) = 369.6 ft3
Dividing this by the volume of the wheelbarrow
369.6 ft3 / 9 ft3 = 41.07
He would need to use the wheelbarrow 42 times.
        
             
        
        
        
Answer:
30..? sorry im not quite sure what youre asking