You are conducting interviews. If the candidate is qualified it takes 30 minutes to interview the candidate. If the candidate is not qualified it takes 10 minutes to interview the candidate. Create a function for this scenario, then calculate the expected value. The mean is 17.

My best guess on the formula is T = 30y + 10z.

I know this does not work with calculating the expected value because the z needs to be y to do an expected value calculation. Can I please have some ideas with this?