[Goatracer1]

These may seem like simple questions but there may be other factors to consider that I don't know about. 1)If I mix equal amounts of 87 octane gasoline and 93 octane gasoline will I get 90 octane gasoline? The reason I ask is that in my area mixing the 87 and 93 is cheaper than buying 89 octane (plus it is a point higher). 2) Will mixing 10-30 motor oil and 15-50 motor oil (same brand and type) give me 12.5-40 oil? The reason I ask this is because I have a lot of 15-50 I don't want to use. Thanks for any input.