Data Sufficiency (DS) | What are the roots of the quadratic equation x^2 + bx + c = 0 if the

May 31, 2019, 1:00 am

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kiran120680 wrote:

What are the roots of the quadratic equation x^2 + bx + c = 0 if the roots are distinct and at equal distance from 5 on the number line?

(1) The product of the roots of the equation x^2 + bx + c = 0 is 21

(2) x – 7 is a factor of the expression x^2 + bx + c

D. Each independently sufficient.

1. x1 * x2 = 21 Possible: (21,1) (3,7). Only (3,7) are distinct roots equidistant from 5.
Alternatively solve (5+x)(5-x)=21

2. If x1= 7, x2 can be 7 or 3. Only (3,7) are distinct roots equidistant from
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Problem Solving (PS) | Re: How many pairs of real numbers (x, y) satisfy the equation [m](x + y)^

May 31, 2019, 1:00 am

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let x+3=A and(y-3)=B
(x+3)+(y-3)=x+y
A+B=x+y

$(x + y)^2$ = (x + 3) (y –3)
$(A+B)^2$ =AB.....(1)
From (1) AB must be either equal to 0 or greater than0.....(2)
$A^2+B^2+2AB$=AB
$A^2+B^2+AB$=0
$A^2$ ,$B^2$ and AB are non- negative terms and their sum is equal to 0. It's only possible when all of them are equal to 0.
We get A=0 and B=0
x+3=0, x=-3 and y-3=0, y=3 is the only possible solution.

nick1816 wrote:

How many pairs of real numbers (x, y) satisfy the equation$(x + y)^2$ = (x + 3) (y – 3)

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Data Sufficiency (DS) | Re: What is the sum of the digits of the positive integer n

May 31, 2019, 1:00 am

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Mohammad Ali Khan wrote:

GMATNinja wrote:

I think your conclusion is correct, harsh6239, though I'm pretty sure that this is an MGMAT question, and I found a slightly different version of it elsewhere:

What is the sum of the digits of the positive integer n where n < 99?

(1) n is divisible by the square of theprime number y.
(2) y^4 is a two-digit odd integer.

So if we go with the version that specifies that y is prime, then...

Statement 1: y could be any number of primes, which means that n must be divisible by

...

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Data Sufficiency (DS) | Re: If X = (9b - 3ab) / (3/a - a/3), what is x?

May 31, 2019, 1:00 am

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Tactic101 wrote:

If x = 9b - 3ab / (3/a - a/3), what is x?

(1) 9ab / 3+a = 18/5
(2) b = 1

x = 9b - 3ab / (3/a - a/3)
= 3b(3 - a)/{(9 - a^2)/3a}
= 9ab/(3 + a)

(1) 9ab / 3+a = 18/5
—> x = 18/5.
Sufficient

(2) b = 1
We don’t know the value of a.
So, Insufficient

IMO Option A.

Pls Hit kudos if you like the solution

Posted from my mobile device

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Problem Solving (PS) | A and B each have some coins. The number of coins A has is the square

May 31, 2019, 1:00 am

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A and B each have some coins. The number of coins A has is the square of number of coins that B has. The total number of coins they have between them is a multiple of 100. What is the smallest total number of coins they could have?

A. 200
B. 300
C. 400
D. 500
E. 600

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Problem Solving (PS) | Re: x is at least 50% greater than 100, and at most 100 % greater than 100

May 31, 2019, 1:00 am

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x is at least 50% greater than 100- Doesn't it mean that X>150?
I don't think x will include 150 also.
Please help clear this doubt.

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Problem Solving (PS) | Re: A bag contains 3 white balls, 3 black balls & 2 red balls

May 31, 2019, 1:00 am

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Data Sufficiency (DS) | Re: One-sixth of the orders placed at a take-out restaurant on Friday

May 31, 2019, 1:00 am

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Shrey9 wrote:

shridhar786 wrote:

One-sixth of the orders placed at a take-out restaurant on Friday night had a value of less than $15. How many orders were placed on Friday night?

(1) The number of orders with a value of less than $17 was 5

(2) The number of orders with a value of more than $20 was 21

Hi, here is my take, which doesn't match the OA

We need to find total number of orders placed on a Friday night.

If 1/6th orders are worth less than $15
then 5/6th must be greater than or equal to $15.

Now
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Problem Solving (PS) | Re: Mrs. Smith has been given film vouchers. Each voucher allows

May 31, 2019, 1:00 am

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PriyankaPalit7 wrote:

chetan2u ,VeritasKarishma ,Bunuel ,Gladiator59 ,generis

Why are we assuming that 120 ways to distribute the remaining vouchers, after Mrs Smith has already distributed 2 vouchers per head?

...

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Data Sufficiency (DS) | Re: A certain x-liter solution, contains twice as much water as oil and fo

June 1, 2019, 1:00 am

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Bunuel wrote:

teone83 wrote:

Bunuel wrote:

A certain x-liter solution, contains twice as much water as oil and four times as much oil as vinegar, what is x?

(1) The solution contains 5 liters of oil.
(2) The solution contains 60 percent water.

Hi Bunuel, from statement 2 I obtain something like this : since the ratio of oil to water to vinegar is 4x:8x:x and statement 2 states "water = 0.6 total " we can write

8x = 0.6 * 13x

which is never verified for any x unless x= 0 ...so I think this statement contradicts the first
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Data Sufficiency (DS) | Re: A department manager distributed a number of books, calendars, and dia

June 1, 2019, 1:00 am

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I have another approach to solve this type of DS question easier.

The question term requires "How many staff members were in the department?" which is referred to "count information". So, it needs count information as an input.
+Statement 1: we know the ratio of each item, no count information. Insufficient data, A & D are out.
+Statement 2: after simplifying the ratio 18:27:36, we have the same ratio 2:3:4, still no count information-->Insufficient data, B is out.
As
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Problem Solving (PS) | Re: The product of the squares of two positive integers is 400. How many

June 1, 2019, 1:00 am

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lets say 2 numbers are x and y.

So the equation is , x^2 * y^2 = 400
xy = 20

20 can be written as 1X20, 2X10, and 4X5, so 3 ways.

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Quantitative | Re: Short Videos by Experts' Global - GMAT Shots | Quantitative

June 1, 2019, 1:00 am

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Dear All,

Please see the concept of How to Find Last Digits of Large Powers and Exponents explained in the following short video:

Iframe

Hope this helps.

All the best!
Experts' Global

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Data Sufficiency (DS) | Re: A pentagon with 5 sides of equal length and 5 interior angles of equal

June 1, 2019, 1:00 am

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Bunuel wrote:

A pentagon with 5 sides of equal length and 5 interior angles of equal measure is inscribed in a circle. Is the perimeter of the pentagon greater than 26 centimeters?

(1) The area of the circle is 16π square centimeters.
(2) The length of each diagonal of the pentagon is less than 8 centimeters.

DS75271.01
OG2020 NEW QUESTION

VeritasKarishma :

All the solutions provided are difficult to understand. Is there any other way to solve statement 2?
After looking all these, I thought I will and
...

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Problem Solving (PS) | Re: 1 unit of x% alcohol is mixed with 3 units of y% alcohol to give 60%

June 1, 2019, 1:00 am

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nick1816 wrote:

x.........y
....60....
1.........3

$\frac{x-60}{60-y}$ =3/1
x+3y=240...(1)
x=240-3y=3(80-y)

We have 2 constraints
1. x=<100
2. x>y
Also, x will be a multiple of 3

x can be 99,96.....63
At x=60, y=60....Hence x can't take value equal to 60 or lower than 60.
Total number of integer values x can take=[$\frac{99-63}{3}$ ]+1=13

DisciplinedPrep wrote:

1 unit of x% alcohol is mixed with 3 units of y% alcohol to give 60% alcohol. If x > y, how many integer values can x take?

A. 10
B. 20
C.

ote]

]Why
...

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Data Sufficiency (DS) | Re: Is a - b > 0?

June 1, 2019, 1:00 am

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Problem Solving (PS) | Re: There are 6 people at a party sitting at a round table with 6 seats: A

June 1, 2019, 1:00 am

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VeritasKarishma wrote:

mrdanielkim wrote:

i figured it out after taking a break from studying. thanks anyway!

here's the solution anyway, though the book has the question worded differently:

Q: IN how many ways can 6 people be seated at a round table if one of those seated cannot sit next to two of the other five:

A: Six people can be seated around a round table in 5! ways. there are 2 ways that the two unwelcome people could sit next to the person in question and 3! ways of arranging the other

tracted from the base
...

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