Question

Setting up the math for a two-step quantitative problem
Picture attached
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Answer 1

I don't think the altitude matters.

Start with 550km. We want to write conversion factors, cancelling out units until we get L as our final unit. It travels 2200 km/hr, which means we can write 1hr/2200km as a conversion factor.

If you multiply 500 km * (1hr/2200km) you get hours.

Repeat with the appropriate hours ---> minutes conversion factor and then the minutes ---> L conversion factor

I'll help you if you get stuck

Answer 2

review dimensional analysis when you get a chance

you're in hours now ---> multiply by (60 min/1 hour) to get into minutes

then, since the plane burns 37.9L/min, you can multiply by 37.9L/min to get into L

Answer 3

I don't understand where to even start with. how did you know to start with 550?

Answer 4

Typically you don't start with conversion factors. We are given the flat quantity 550km, while 2200km/hr and 37.9 L/min are conversion factors/rates.

If I want to convert my height from feet to inches, I start with my height, not 1 foot/12 inches.

Answer 5

Let me try this out without reading your whole explanation. The one you just clarified helped alot.

Answer 6

(that being said, if they, for example, tell you to convert a rate like mpg to km/L then you need to start with that rate)

Answer 7

...never mind

Answer 8

Sorry if that was confusing ^_^ I think it'll come with practice/experience.

Answer 9

No no, you're extremely helpful. My chemistry professor doesn't do jack and I haven't taken chemistry in three years now I believe? So it's extremely rusty to me.

Answer 10

So this is me primarily guessing, but I got

Answer 11

(idk why I made it cut off)
\[500km*\frac{ 1 hr }{ 2200km }*\frac{ 60\min }{ 1 hr }*\frac{ 37.9L }{ 1\min }\]

Answer 12

But again, I feel like I'm wrong because I'm just flipping values left and right

Answer 13

Yep, that's what I got too

IDK if this helps at all, but I like to think of conversion factors as equal to 1 (1 km """equals""" 2200km so 1hr/2200km and 2200km/hr are both "equal" to 1, I just pick the one I need based on what units cancel out)

Answer 14

*1 hr "equals" 2200km

Answer 15

OH OKAY THATS WHAT I DID. I thought it wasn't right because I thought placements matter like that. But to think of it it's right. at least I hope lol

Answer 16

Placements do matter, just remember to re-arrange based on what you need to cancel out

Answer 17

Like, because we have 550km in the numerator, we have to pick 1 hr/2200km to cancel out km, otherwise if we pick 550 km * 2200km/hr we get km^2/hr as the unit which isn't helpful here

Answer 18

Oh yes, that too. But I just checked and we were right. Thank you so much!!! <3 It was the one lesson I was extremely stuck on