

Thus, the final answers are 1 and -1/8.
 
        
             
        
        
        
Answer:
3.08 km/h.
Step-by-step explanation:
We know that,
 
Ali traveled at a speed of s km/h for 2.5 hours.
Let d be the distance and t be the time.
 
 ...(1)
      ...(1)
On his return journey, he increased his speed by 4 km/h and saved 15 minutes. So, distance is d and times is t-15.
 
 ...(2)
      ...(2)
From (1) and (2), we get
 
 
 
 
Put t=40 in (1).
 
So, t=40 and d=100.
Now,
Total distance = d + d = 100 + 100 = 200
Total time = t + t - 15 = 40 + 40 - 15 = 65
So, the average speed is
 
 
 
Therefore, the average speed is 3.08 km/h.
 
        
             
        
        
        
Answer:
b) Commutative property is true for subtraction of Rational numbers 
Step-by-step explanation:
- Option B is incorrect.
- Commutative property is not true for subtraction of Rational numbers .
 
        
                    
             
        
        
        
Answer:
see explanation
Step-by-step explanation:
The meaning of n factorial → n !
n ! = n(n - 1)(n - 2)........ × 3 × 2 × 1
For example
7 !
= 7 × 6 × 5 × 4 × 3 × 2 × 1 
 
        
             
        
        
        
Answer:
n = 3
Step-by-step explanation: