Practice Questions Chat

Is \(m \lt 0\)?

(1) \(-m=|-m|\).

Firstly, \(|-m|=|m|\), (for example: \(|-3|=|3|=3\)), so we can rewrite the statement as \(-m=|m|\). Since \(|x| = -x\) when \(x \leq 0\), then \(-m=|m|\) implies \(m \leq 0\). Therefore, \(m\) could be either negative, giving a YES answer to the question, or zero, giving a NO answer to the question. This statement is not sufficient.

(2) \(m^2=9\).

The above implies that either \(m=3\) (positive) or \(m=-3\) (negative). This information alone is not sufficient to answer the question.

(1)+(2) We know from (1) that \(m \leq 0\), and from (2) we have two possibilities: \(m=3\) or \(m=-3\). Since \(m \leq 0\), we can eliminate \(m=3\), leaving us with \(m=-3\), which is negative. Thus, the answer to the question "is \(m \lt 0\)" is YES. Sufficient.

Answer: C.

Hope it's clear.

P.S. Discussed in detail here: https://gmatclub.com/forum/is-m-0-1-m-m-2-m-99913.html

● Karina is deciding whether to use Brand A or Brand B motor oil in her car. Brand A costs 50% more per liter than Brand B. But, according to the recommendations for frequency of oil changes, if she uses Brand A, she will be able to drive 2.5 times as many kilometers before she changes her oil as she will if she uses Brand B. The cost per kilometer driven is what percent less when using Brand A than when using Brand B ?

This question is discussed here: https://gmatclub.com/forum/karina-is-de ... 15057.html Hope it helps.

A researcher plans to identify each participant in a certain medical experiment with a code consisting of either a single letter or a pair of distinct letters written in alphabetical order. What is the least number of letters that can be used if there are 12 participants, and each participant is to receive a different code?

Why doesn’t order of the letters don’t matter here?

Because they have told letters are written in alphabetical order. A-B cant be B-A, so it’s a combination problem IMO

This question is discussed in great detail here: https://gmatclub.com/forum/a-researcher ... 34584.html Hope it helps.

Guyzz don’t ever take expert global mocks they will confuse you because they have only 700-800 level questions in every mock

i think quants are very good

for expert global mocks

verbal RC again good , cant say for CR and SC

howz ur variation from prep mocks in total ?

The total distance between Matt’s and John’s houses was 3 kilometers. Matt left his house at 10 a.m. to go towards John’s house and met John on the way. The walking speed of John was 1.5 meters per second, and the walking speed of Matt was 1 meter per second. If John left his house at 10:10 a.m.to walk towards Matt’s house, at approximately what time would they meet?

Why is this 10:26?

Time to meet = Remaining distance/ combined speed.
= 2400m/ 2.5m/s. = 960 sec.
Total time = 10+ 16 min = 26 min.

how do you get 2400m?

In 10 min, matt walked 600m, so 3000-600=2400.

Sorry, I don’t get your solution and how you got to it...

Distance covered by Matt in 10 min = 600 m( He walks 10 min at the speed of 1m/s)
Remaining distance = 3000-600=2400m.
Now, the time taken for them to meet = Remaining Distance/ Combined Speed.
Combined Speed = 1.5+ 1 = 2.5m/s.
= 2400/2.5 = 960 sec = 16 min.
Time taken = Time Matt+ 16 min =
10+ 16 = 26 min.
Therefore, they meet at 10:26 min. i hope you got it now.

This ques can be solved by using matrix method