Because 50% of something means half (because 100-50=50), he would have to make the number of girls and boys equal. Since there are 21 girls, he has to make it so there are also 21 boys. 
So, if we know that 21-15=6, this means he would have to add 6 boys to the club if he wants the girls and boys equal.
        
             
        
        
        
Answer:
s = - 1 ± 
Step-by-step explanation:
Given
s² + 2s - 6 = 0 ( add 6 to both sides )
s² + 2s = 6
To complete the square
add ( half the coefficient of the s- term )² to both sides
s² + 2(1)s + 1 = 6 + 1
(s + 1)² = 7 ( take the square root of both sides )
s + 1 = ±  ( subtract 1 from both sides )
 ( subtract 1 from both sides )
s = - 1 ± 
Thus
s = - 1 -  , s = - 1 +
 , s = - 1 + 
 
        
             
        
        
        
You must mean the depth of the submarine.
to make  sum = zero the depth of the sub must be -1600 ft..
        
                    
             
        
        
        
The path of the car and the limo are straight lines.
To determine the equation of the lines of the paths, the slopes must be determined.
Let m1 = slope of car
m2 = slope of limo
so,
m1 = (7 + 7)/(5 + 2) = 2
m2 = (-5 -9)/(3+4) = -2
therefore the equations are
car:
2x – y = 2(5) –(7)
2x – y = 3
Limo:
2x + y = 2(3) – 5
2x + y = 1
Solving the intersection of the equations (using a calculator)
x = 1
y = -1
        
                    
             
        
        
        
The probability of drawing a 5 from card numbered 1 - 10 is 1/10 because only one card out of ten is numbered 5. 
The probability of rolling a 2 on the cube is 1/6 because there are 6 faces of the cube with 6 different numbers. The probability of picking a 5 and rolling a 2 together is 1/60 because 
1/10 x 1/6 = 1/60. You multiply them together because there will be 60 combinations: 10 card possibilities and 6 cube possibilities. 
Hope this helps!