Question 1207330
Let x  be the volume in A after pouring into B
Let y be the volume in B  after pouring
Full volume in A = L*w*h =30000

x+y =30000

Volume in A after pouring 
x = A*h
x = h*25*30
x = 750h
h = x/750


Volume in B = h *25*18
y = 450h

h= y/450

Heights are same after pouring

x/750 = y/450

x = y*750/450

x = 5y/3

x+y =30000    ( full volume in A)
substitute x

5y/ 3 + y = 30000


8y/3 = 30000

8y = 90000
y = 90000/8
y=11250  ( Volume in B after pouring)


x = 30000-11250
x=18750  (volume in A after pouring)

Volume / area = h

18750/750 = 25

Volume in B = 30000-18750 =11250

h= 11250/450 =25

Height same after pouring