Mother with good credit younger daughter bad credit

[Ryan Ogilvie]

I am currently looking for tenants for one side of my duplex and have a question. I have one interested applicant that qualifies for my minimum standards (3x income-rent, credit score about 600) but has a 20 something year old daughter that will also be living with her that does not qualify based on credit score. The mother says she will be the one paying all the rent. Should I allow them? Is there a way to set up the lease to have the mother responsible for all finances and the daughter just a tenant? Thanks