Answer:
- 0.5
Step-by-step explanation:
you first change the fractions numbers  in to decimal form
       so;   2/5 = 0.4
                -7/8 = - 0.875
hence;   0.4 + (-0.875)
              = - 0.475
in to its simplest form   =  - 0.5
   the answer is  - 0.5
 
        
             
        
        
        
Answer: 81.85 km/hr
Converting m/sec into km/hr, 25 m/sec = 90 km/hr
Average = 
Time = 50/90  =  5/9 hr
next 120 km at an average speed of 80km/h
=> Time = 120/80  = 3/2  hr
last part of its journey at an average speed of 90km/h in 35 Minutes
time = 35 minutes = 35/60 hr = 7/12 hr
Distance covered = 90 * 7 /12  = 105/2  km
Total Distance = 50 + 120  + 105/2  = 435/2 km
Total time = 5/9 + 3/2 + 7/12   =  ( 20 + 54 + 21) /36  = 95/36
Average speed =   (435/2)/(95 /36)  = 432 * 18  /95 = 81.85 km/hr
 
        
             
        
        
        
0.002%. Just take 0.6/300 and input into a calculator.
        
                    
             
        
        
        
1-1, 1-2, 1-3, 1-4 and u should Change it to middle school