GMAT Practice Qs

Question

Hi There,

I have just taken the GMAT practice test 2 but have a number of Qs that I did not understand the answer to - was wondering if anyone could help on these.....

1) Square S is inscribed in Circle T. If perimeter of S is 24, what is the circumference of T?
not sure why is it not pi6, but pi 6 sq. rt 2?

2) 3^x-3^x-1 = 162, then x(x-1)= ? not sure how to answer this at all..

3) on a number line,the segment 0 to 1 is split into both fifths and sevenths. what is the least distance between any two segments? not sure why answer is 1/35 instead of 2/35 which is what I got subtracting 1/5 - 1/7

Thanks!

sharmishtha_goel · Answer

1) as the square S is inscribed in the circle, its diagonal is the diameter of the circle.
perimeter of S is 24, hence its diagonal is 6 sqrt(2) . therefore, the radius of the circle is 3 sqrt(2). So, the circumference is 6 pi sqrt (2).

2) no clue either!!

3) 3/7 - 2/5 = 1/35
for easier calculation, assume 35 units btw 0 and 1. (35 is the LCM of 5 and 7 )

hope that helps.

Anurag@Gurome · Answer

felixtse wrote:1) Square S is inscribed in Circle T. If perimeter of S is 24, what is the circumference of T?

As square S is inscribed inside the circle T, the length of the diameter of the circle will be equal to the length of the diagonal of the square.

Now, perimeter of the square = 24
Hence, length of a side of the square = 24/4 = 6
Hence, length of the diagonal of the square = 6√2 = the length of the diameter of the circle

Therefore, the circumference of the circle = π*6√2

Anurag@Gurome · Answer

felixtse wrote:2) 3^x-3^x-1 = 162, then x(x-1)= ?

I assume the actual expression is 3^x - 3^(x - 1) = 162

--> 3^x - 3^(x - 1) = 162
--> 3^x - (3^x)/3 = 162
--> (3^x)(1 - 1/3) = 162
--> (3^x)(2/3) = 162
--> 3^x = 162*3/2 = 243 = 3^5
--> x = 5

Hence, x(x - 1) = 5*4 = 20

Anurag@Gurome · Answer

felixtse wrote:3) on a number line,the segment 0 to 1 is split into both fifths and sevenths. what is the least distance between any two segments? Refer to the post here : https://www.beatthegmat.com/post348618.html#348618

felixtse · Answer

Thanks!

I just had a few more qs....

1.
For a certain race, 3 teams were allowed to enter 3 members each. A team earned 6-n points whenever one of its members finished in nth place , where 1 <_ n<_6
There were no ties, disqualifications or draws
If no teams earned more than 6 points, what is the least possible score a team earned?

2.
In a survey of 248 people, 156 are married, 70 are self-employed, and 25% of those married are self employed. What is the probability the person will be self –employed but not married?

Answer is 1/8
I answered by subtracting 75% married and self-employed (ie 39) from 70 which should come up with 41/248; approx 1/8？

3.
In the infinite sequence a1,a2….an, each term after the first is twice the previous term. If a5-a2 = 12, what is a1?

Answer is 24/7 – not sure why?
Tried to answer by plugging answer choices but didn’t come up with the right answer.

blaster · Answer

felixtse wrote:Thanks!

2.
In a survey of 248 people, 156 are married, 70 are self-employed, and 25% of those married are self employed. What is the probability the person will be self –employed but not married?

Answer is 1/8
I answered by subtracting 75% married and self-employed (ie 39) from 70 which should come up with 41/248; approx 1/8？

it should be 31,not 41.
70-39=31

therefore 31/248=1/8

pm · Answer

1. 3 2. 1/8 3. 6/7 See this https://www.beatthegmat.com/in-the-infin ... 51253.html

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