#### 2 hours
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- Rate of Pipe B = \( 1/6 \) of the tank per hour
- Combined rate = \( 1/3 + 1/6 = 1/2 \) of the tank per hour
- Time to fill the tank = \( 1 / (1/2) = 2 \) hours
- A quadratic equation \( x^2 - 5x + 6 = 0 \) has roots \( a \) and \( b \). What is the value of \( a^2 + b^2 \)?
- Use the identity \( a^2 + b^2 = (a+b)^2 - 2ab \)
- From the equation, \( a+b = 5 \) and \( ab = 6 \)
