A manager has 3 daughters. The manager name is Bob.
- Sum of Each daughter's age is 13.
- Product of Each daughter's age is the Bob's age number.
The manager's assistant Alice knows Bob's age, but still cannot tell the age of each his daughter. At this moment, Bob told Alice that only one daughter's age is capable to read newspaper. Now Alice knows all Bob's daughters age.
Q: What is Bob's age?