The answer is 16 inches.
Let r be a radius and h be a height of a cylinder
Since the cylinders are similar, then the ratio between their radiuses is equal to the ratio of their heights:
r1 : r2 = h1 : h2
Cylinder A:
r1 = 5.6 in
h1 = ?
Cylinder B:
r2 = 1.4 in
h2 = 4 in
5.6 : 1.4 = h1 : 4
h1 = 4 * 5.6 : 1.4
h1 = 16 inches
        
                    
             
        
        
        
Take the as together and take the bs together.
5a + 3b - 6a - b.
5a - 6a + 3b - b.  Then simplify.
-a + 2b.
That's it.
        
             
        
        
        
Answer:
There are 21 students.
Step-by-step explanation:
If there are 21 students, and each of them had $21 then this would equal a total of $441 because 21 multiplied by 21 equals 441.
Hope this helps,
Trey