A businessman donated 2% of his money to Charity X. He then donated 4% of his remaining money to Charity Y. Finally, he donated 6% of his remaining money to Charity Z. What percentage of his original amount of money was donated to Charity Z? Give your answer correct to 3 significant figures.

Let's assume the businessman's original amount of money is $1.

Step 1: Donation to Charity X
2% of $1 is \frac{2}{100} \times 1 = 0.02

After donating to Charity X, the businessman has $1 - 0.02 = 0.98 remaining.

Step 2: Donation to Charity Y
4% of $0.98 is \frac{4}{100} \times 0.98 = 0.0392

After donating to Charity Y, the businessman has $0.98 - 0.0392 = 0.9408 remaining.

Step 3: Donation to Charity Z
6% of $0.9408 is \frac{6}{100} \times 0.9408 = 0.056448

Therefore, the businessman donated 0.056448 out of his original amount of $1 to Charity Z.

Answer: The percentage of his original amount of money donated to Charity Z is 5.645%.