Hi Rishab2409,Good news: your numbers are all correct, and the way you're thinking about it is valid
here. But it's worth knowing
why it works, so you don't misapply it on a similar-looking question.
Your idea is that the price tracks the orange-juice concentration:
- Day 1:
50% OJ -
$0.60- Day 2:
33.33% OJ -
$0.40- (Pure OJ,
100% -
$1.20)
That's exactly the answer, so nothing is broken. Here's the reason it lines up.
Why concentration works as a stand-inThe real driver in this problem is
total volume, because the number of glasses is proportional to how much orangeade you make. Since revenue is equal on both days:
price × glasses = constant, so
price is inversely proportional to volume.Now look at concentration. Concentration = (orange juice) ÷ (total volume). The catch is that
the amount of orange juice is the same on both days - that's stated in the problem. With OJ fixed, concentration is just OJ ÷ volume, which means
concentration is itself inversely proportional to volume.So both "price" and "concentration" move the same way - both scale as 1/volume. That's why price ∝ concentration gives you the right number. Check it: concentration ratio = (
1/3) ÷ (
1/2) =
2/3, and
0.60 ×
2/3 =
0.40. Same
2/3 you'd get from the volume ratio (
2 parts -
3 parts).
The one thing to watchYour shortcut leans entirely on the OJ amount being
constant across days. If a future question changed the amount of orange juice each day, concentration would no longer track 1/volume, and this reasoning would give the wrong price. So the safe, always-works version is:
equal revenue - price ∝ 1/volume.So yes - your understanding is correct, just anchor it to the constant orange juice, not to concentration on its own.
Answer: DRishab2409
Hi Bunuel - just wanted to know if this understanding is correct,
For a 50% percent orange juice, the cost is $.6, in case of 100% the cost becomes $1.2 and in case of 33.33% the cost becomes $.40.