Formula mixing

Hi i was eondering if i can mix ready made formula with podwer formula in the same bottle ? Like 2 oz of ready made plus making 2 oz of podwer with water in the same bottle

Is because i have ready made formula that i have to use before it goes bad but my baby doesnt like it she only likes the podwer made one and i feel bad waisting the ready made can anyone help please new mom here