I don't know where to find those number on my keyboard so I will subsitute
€=x£=y¥=zso
1x=0.89y
and 1y=48z
first find conversion factor from z to x
1x=0.89y
y=48z
subsitute 48z for y in first equation
x=0.89(48z)
x=42.72z
divide both sides by 42.72
x/42.72=z
256z is wanted so
multiply both sides by 256
x/1 times 256/42.72=256z
5.99251x=256z
there are aprox 5.99x in 256z or about 6