Answer:
Step-by-step explanation:
Time for first race 57.9seconds
x=time for first half of race
x-4.7=second half of race
Equations is
x + (x-4.7)=57.9
2x-4.7=57.9
2x=57.9+4.7
2x=62.6
x=31.3
Check answer
31.3 + (31.3-4.7)=57.9
31.3 +26.6=57.9
57.9=57.9
 
        
             
        
        
        
65 total test items were on the test.
 
        
        
        
You need to find the total distance and the total time. The total distance is two times the distance to school, 2d.s=d/t=>t=d/sWhere s is speed, d is distance and t is time. So the time taken to get to school is:d/s1and the time taken to get back is:d/s2so the total time is:d/s1+d/s2=d(1/s1+1/s2)So, as speed = distance/time, divide the total distance by the total time:2d/d(1/s1+1/s2)=2/(1/s1+1/s2)=2/(1/20+1/40)=80/3≈26.7km/hr
        
             
        
        
        
3.122
The process to getting this comes in many steps. Firstly, you need to find the angles for JLK and MLJ. To find JLK use the arcsin function using the opposite side and the hypotenuse. 
Arcsin(Opp/Hype) = JLK
Arcsin(.5) = JLK
30 degrees = JLK
This means MLJ = 31 degrees since they add up to 61 degrees. 
Now we need to find the length of LJ, which we can do using the Pythagorean Theorem. 
3^2 + JL^2 = 6^2
9 + JL^2 = 36
JL^2 = 27
JL = 

Now that we have the angle of MLJ and the length of JL, we can use the tangent function to find MJ.
Tan(angle) = opp/adj
Tan(31) = MJ/


Tan(31) = MJ
3.122 = MJ
 
        
        
        
55
Step-by-step explanation: