solution:
[tex]Amount of purified acid phosphatase added to tube A = 5\mu g(micrograms)\\
Amount of acid phosphatase present in 400\mu g of wheat germ extract in tube B=1/100=5x/400\\
100x=(0.5)(400)\\
X=(0.5)(400)/100=2\mu g\\
The amount of acid phosphatase present in 400\mu g of the wheat germ extract in tube B is 2\mu g[/tex]