well, first of all, you don't want to go into the oven, is too hot and you'll get burned, so you may not want to do that.
now, if we start to bake something at 3:40pm and it requires 35 minutes, it'll be done by 3:40 + 35, or 3pm and 40 + 35 minutes, or 3pm plus 75 minutes or 3pm plus 60 + 15 minutes, but since 60 minutes is 1hr, that'd be 3pm plus 1hr plus 15 minutes, 4:15pm.