11 liters of 25% orange juice, 4 liters of 10% orange juice:
1' let x to be 25% orange juice and y be 10% orange juice
2' .25x+.10y=(15).21
3' x+y=15
4' 2.5x+y=31.5 divide all sides by 10
5' -x-y=-15 multiply all sides by -1
6' 1.5x=16.5
7' x=11
8' y=15-11=4
so 11 and 4 are the answers.
        
             
        
        
        
Answer:
c is the answer
Step-by-step explanation:
 
        
             
        
        
        
Answer:
answer is : Cos(13pi/8) = 0.3826   
Step-by-step explanation:
We have, Cos (13pi/8)
Since 13pi/8 can be shown as 3pi/2 < 13pi/8 < 2pi 
Hence 13pi/8 lies on fourth quadrant.
In fourth quadrant cosine will be positive.
Cos (13pi/8) = cos(3pi/2 + pi/8)
applying formula cos(A+B) = cos A cosB - sinAsinB
i.e Cos(3pi/2 + pi/8) = cos(3pi/2)cos(pi/8) - sin(3pi/2)sin(pi/8)
∵ Remember cos(3pi/2) =0 , sin(3pi/2) = -1 
      Cos(3pi/2 + pi/8) = 0 cos(pi/8) - (-1)sin(pi/8)
      Cos(3pi/2 + pi/8) = 0  + 0.3826
       Cos(3pi/2 + pi/8) = 0.3826
Hence we got Cos(13pi/8) = 0.3826                           
 
 
        
                    
             
        
        
        
Answer:
C or B
Step-by-step explanation: