10m
The process of elimination
        
             
        
        
        
The value of p would be 40. This is because the ratio of p:q = 10:5. this could be simplify into p:q = 2:1. Applying the ratio p:20 = 2:1, P=40.
        
             
        
        
        
Answer:
The initial speed of the car was 80 ft/s.
Step-by-step explanation:
The deceleration is the rate at which the car speed decreases. In this case the speed of the car goes all the way down to 0 ft/s and in order to do that it travelled 50 ft.  So we will call the initial speed at which the car started to brake "v_0" and use Torricelli's equation to find it. The equation is given by:
v^2 = (v_0)^2 + 2*a*S
Where v is the final speed, v_0 is the initial speed, a is the rate of acceleration and S is the space travelled. Using the values that the problem gave to us we have:
0^2 = (v_0)^2 - 2*64*50 
0 = (v_0)^2 - 6400
(v_0)^2 = 6400
v_0 = sqrt(6400) = 80 ft/s
Notice that in this case "a" was negative, since the car was decelerating instead of accelerating.
The initial speed of the car was 80 ft/s.
 
        
                    
             
        
        
        
Your diagram doesn't clearly define what values correspond to what, can you explain.