Answer: A. divided the difference of the two quantities by the sum of the two quantities. 
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Explanation:
The difference of the quantities is 20-15 = 5
The sum of the quantities is 20+15 = 35
Dividing those results leads to 5/35 = 0.142857 which rounds to 0.1429
That converts to 14.29%
This is likely the path Adam took. This path is incorrect. The correct steps are shown below
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Difference = 20-15 = 5
Divide the difference over the original quantity
5/20 = 1/4 = 0.25 = 25%
We have a 25% decrease because the new quantity (15) is smaller than the old quantity (20)
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Here's another way to approach the problem
A = old value = 20
B = new value = 15
C = percent change
C = [ (B-A)/A ] * 100%
C = [ (15-20)/20 ] * 100%
C = (-5/20)*100%
C = -0.25*100%
C = -25%
The negative C value means we have a negative percent change, ie we have a percent decrease. So this is another way to get a 25% decrease.
 
        
                    
             
        
        
        
Every triangle have three angles that add up to 180°. With this information, we can find out the missing angle.
The sum of three angles should add up to 180°. 
148° + 11° + K = 180°
Where k is the missing angle.
Solve for K.
Combine like terms.
148° + 11° + K = 180°
159° + K = 180°
Subtract both sides by 159°.
159° + K = 180°
159° - 159° + K = 180° - 159°
K = 21°
So, the missing length is 21°.
        
             
        
        
        
Answer:
70
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
D
Step-by-step explanation:
Hope this helps!
:)
 
        
             
        
        
        
If there are 18 students every one of the will pair up with 17 other students throughout the year so the total amount of pairs that can be made is 18x17=306 but since it’s not important if student A is paired with student B or student B with student A we should divide the total amount of pairs by two- 306:2=153 so in total there will be 153 projects finished