Largest resistor value such that BJT remains in active mode

[theBEAST]

Homework Statement

We are given that the transistor has β = 30. The BJT is shown below (along with the solution). Every value in the figure is given with the exception of the equation I circled in red:

The Attempt at a Solution

What I don't get is how they got the inequality Vc - Vb > 0.4V? Where does this come from? I thought saturation occurs when Vce reaches 0.2V, so shouldn't our inequality be Ve - Vc > 0.2V?

 

[NoPoke]

Assume that the magnitude of the base-emitter voltage for the BJT is largely constant. What value might you choose?

 

[NascentOxygen]

I thought saturation occurs when Vce reaches 0.2V?

You are probably right. So at saturation what would be the voltage between C and B? Work it out for a silicon transistor.