Quant Question of the Day Chat

1) There must be 2 C machines. However, we cannot determine the exact amount - there could be 4 B machines, or 6A machines, or some combination. Therefore INS.
2) Gives us a ratio, but no further info. INS.
3) From 1 we know that there are 2 C machines. That means we need 4 B machines. 4 B machines gives us exactly 4800 cans/min, therefore there must be 2 C machines and 4 B machines.

Good reminder that you need to read the question :facepalm_man:

We are told that Alex travels at 4 miles per hour, and has traveled for 1 hour prior to Brenda.
Therefore, he will travel X miles at 4(t+1)=x -> 4t+4=x

We want double the distance of Alexa, so Brenda will have to travel 2x miles at rate R.
Therefore:
Rt=2(4t+4)
Rt=8t+8
t=(8/R-8)

Now don’t make the same mistake I did. That T is the time it takes for Brenda to travel double the distance of Alex. We want the total time Alex has traveled. Remember, Alex traveled 1 extra hour, therefore:
(8/R-8)+1=(8+R-8/(R-8))=R/(R-8)

Answer C.

I would say this question is probably best solved via plugging in numbers, but I didn’t try that method

oh boy ! I too made that error (rushed to mark D only to realize that reading question carefully is so important)

DS Question 2 - Dec 23

If x is a non-zero integer, what is the value of x?

(1) x^(4x) = x^(16)
(2) (x^x)(x^2) = x^6

Source: GMATPrepNow | Difficulty: Hard

Yep! Such an easy error to make too - since it’s one of the answer choices

Wouldn’t surprise me if this question was 30% accuracy just based off wording :p

I’m always weary when I see GMATPrep Now DS but:

1) if X=1, it is true. However, X=4 and statement 1 would be true. Note that X=-1 is not possible, because RHS would be pos while LHS negative. So X=1 or =4.
2) X can be 1 here as well, or 4.

3) We have no new info combining the two statements. Clearly ins, as there is no way to determine if x is 1 or 4.

E.

Hi, Thanks for the explanation,
But the first statement specifies that there are 4800 cans FILLED. Not that 4800 cans have been installed with lids. Although it is tempting, I’m little hesitant to assume that in parallel 2 machines of C has installed.
Case. 1, I assumed 4800 cans were filled by 400x A machines and 600y B machines. We can’t determine values of x and y. So insufficient

Case 2, Since we have no information of the number of C machines ratio is highly insufficient for determining any number.

Combined, I have derived 4800 = 400x + 600y, Now Let’s just assume your approach then according to case 2 4800 = 2*600*y, y=4 but what about x? It was never mentioned that A machine was not working at all. So how can we assume x=0 for the above?

I think the option could be E.
Let me know if i missed any point

Note that the question says "a lid is installed on every can that is filled". Therefore, if 4800 cans are filled each minute, then 4800 lids must also be installed

If that statement was missing from the stem, then you would be correct.

Furthermore, the question also states that no lids are installed on empty cans - otherwise this would also make the answer E.

small mistake, there should be 6 A machines but I forgot to calculate them. So total is 6A,4B and 2C

Yes, I agree as I stated, that could be tempting to assume.
As the question says “lids can only be installed on filled cans” but we cannot certainly assume viceversa which is “All the filled cans will be installed with lids”

I’m thinking of Data Insufficiency here, 4800 cans are filled but we’re not sure that 2 machines of C are certainly working at the same time. That’s again is assumption.

If stated in question that- “Every filled cans HAVE to be installed with lid AND installation is done simultaneously by machine C as they’re being filled” then it is SAFE to assume that there are C machines working in that minute.

I agree with you that filled cans have to be installed with lids but since it’s unstated in question stem, it creates a benefit of doubt to assume or not. Hence the safest option would be E.

Notice that the question doesnt require for them to be working at the same time

It just says in any given minute

It’s not really an assumption imo - it’s stated in the question

Yes, be it simultaneously or in a minute, we still can’t assume if C is working or not.

We are told that Machine C places lids only on cans that are filled and that each filled can has a lid

Theres no reason why machine C would not be working

If 4800 cans are filled, then those 4800 cans need a lid

Then the case 1, could have been stated like this: 4800 cans have been filled and installed with lids. It would have been good indication that C is working in that minute.
Since it’s left upon us to consider about the number of machines. Only mention of filling the cans could be game changer.

It’s mentioned in the stem

So theres no need to repeat it

I still would stick to what I said, Yes they mentioned “all C machines can ONLY install on filled cans” but stem never said the viceversa that “all the filled cans are to/must be installed”.

I’m waiting for OE to check how to justify case 1 statement.

"DS Question 1 - Dec 23" is an official question and the OE is C

Thanks, can your provide link for official explanation?

Hello there! I am an aspiring enhancing around quant which full over me over the time to solve these tricky question which now have been a hobby for me so could you please share me dec 22 all questions of quant

PS Question 1 - Dec 24

m and n are positive integers. What is the smallest possible value of integer m if m/n = 0.3636363636...?

A. 3
B. 4
C. 7
D. 13
E. 22

Source: GMAT Club Tests | Difficulty: Medium

DS Question 1 - Dec 24

Company M has two divisions - X and Y. Each division has exactly two types of employees - clerks and managers. Is the ratio of clerks to managers greater for division X than that for division Y?

(1) Division X has 20% managers.
(2) Company M has 15% managers.

Source: Expert’s Global | Difficulty: Medium