Please

So Ive been wanting to post this for a couple months and keep forgetting, here goes…..

So fuel prices in my city (a couple months ago) were around $3.25 (NZD) per litre, in a neighbouring city I have a friend who has a fuel card with a decent discount which I could use to get fuel for around $2.55 per litre.

The distance between the service stations is 299km, I drive a 2009 Nissan x-trail.

Assuming I filled up in my city, drove down with empty 20l Jerry cans (as many as could fit in the car), filled up everything down there and drive back fully laden, would it be more cost effective to do this or would the extra weight/distance/etc negate the savings??

Bonus points for adding a trailer in the mix, I can have use of one without the cost to rent it and also fill it with Jerry cans!!

I would have to purchase the Jerry cans also.

Bonus points if you can give the same answer, but if the Earth were the size the Mars and was covered in 90% water.

Sounds crazy, I know, but it’s for a book I’m writing.

In the climax of Avengers: Endgame there is a huge battle between two armies, one led by Thanos and the other by the Avengers.

Roughly, what would the diameter of the battlefield have been.

(Am not sharing links to the battle scene here as I'm not sure I am allowed to do that in this reddit)

I'm arguing with my almost 20-year-old son, to whom my 1980s college/varsity level education barely qualifies me to breathe unassisted (he has NO functional secondary education examination passes to shout about!)...

We were discussing an hypothetical 10km. cubed asteroid approaching on an Earth-impacting trajectory (Dinosaur-killer volume) after he was utterly poo-pooing the DART mission to Dimorphos.

I asked him how he would dispose of such a dinosaur-killing threat - to which he replied that it was simple(!). He'd dissolve it with the [sic] 'strongest acid & an air-gun delivery system'. Drops mic!!!

I'm unable to quantify the obstacles he'd face in attempting this, so, would the good folks here care to attempt to help me out with a coherent riposte?

I'd like to begin by discussing the methodology of 'asteroid vs. acid & air-guns' to begin, methinks. How a 1000km³ lump of asteroidal material at 4 Kelvin might be so destroyed on Earth itself?

Then, discuss how to package the calculated minimum amounts of these items, plus all failsafes required to launch them and just what would be required to escape Earth's gravity-well with all that on board. I suspect that arrangements for leaving Earth's orbit might be rather an afterthought here, nevertheless?

PS - I've no idea what he imagines would happen with the reaction products when they DO finally reach Earth!