How to do an if statement in excel

I'm trying to do an if and statement in excel for a query like this

 If $age = <65 and $income = <90,000 then - 27.82% from $premium

So far I've got

 =IF(AND(E4<65,F4 <90000), 800-27.82%)

but it just gives me

799.7218 as an answer when It should be giving me 577.44