Arranging of books is an illustration of permutation and combination
There are 24 different possible arrangements she can make
<h3>How to calculate the number of arrangement</h3>
The number of books is given as:
n = 4
Take the factorial of both sides
n! = 4!
Evaluate
n! = 4 * 3 * 2 * 1
n! = 24
Hence, there are 24 different possible arrangements she can make
Read more about permutation and combination at:
brainly.com/question/1216161
 
        
             
        
        
        
SOLUTION
At the same time t,
Train 1 would have covered a distance of 80t, since distance = average speed x time.
Train 2 would have covered a distance of 70t.
Now both added should give 210 miles 
That is 80t + 70t = 210
 150t = 210 
 t = 210/150
  t = 1.4 hours
 
        
             
        
        
        
Answer:
769 cubic ft
Step-by-step explanation:
Its volume:
Find the volume of a cylinder of radius 7 ft and length 5 ft:
The basic formula for his volume is V = πr²h.  In this case, the volume is:
V = 3.14(7 ft)²(5 ft) = 769 cubic feet of water.
 
        
             
        
        
        
The answer is 6 shirts 
12.5x+8=83
12.5x=83-8
12.5x=75
x=75/12.5
x=6