Sawaal
4
Q:

 (3x + 2) (2x - 5) = ax² + kx + n .

What is the value of a - n + k ?

A) 5 B) 8
C) 9 D) 10

Answer:   A) 5



Explanation:

This is a quadratic equation. To find n we multiply the last terms in each bracket together (2 times -5) = -10

To find ‘a’ we multiply the first terms in each bracket together (3x times 2x) = 6x2, So a = 6.

Thus a - n = 16

To find k we multiply the first term in the first bracket by the second term in the second bracket and add the result to the product of the second term in the first bracket and the first term in the second. (-15x + 4x) = -11x. So k = -11

16 - 11 = 5

Subject: Problems on Numbers
Exam Prep: GRE
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If the product of 6 integers is negative, at most how many of the integers can be negative?

A) 2 B) 3
C) 4 D) 5
 
Answer & Explanation Answer: D) 5

Explanation:

Multiplying two negatives (or any even multiple) results in a positive. But multiplying three negatives (or any odd multiple) gives a negative. If the result of multiplying 6 negatives is odd, the largest number of negative integers will be the largest odd number (i.e.5)

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Q:

Half the people on a bus get off at each stop after the first, and no one gets on after the first stop. If only one person gets off at stop number 7, how many people got on at the first stop?

A) 128 B) 64
C) 32 D) 16
 
Answer & Explanation Answer: B) 64

Explanation:

7th stop only one was left and in each preceding stop twice the nos... there were so 6 stops before 7th.

 

so 26=64

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Filed Under: Problems on Numbers
Exam Prep: GRE

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Q:

If two painters can complete two rooms in two hours, how many painters would it take to do 18 rooms in 6 hours?

A) 2 painters B) 6 painters
C) 4 painters D) None
 
Answer & Explanation Answer: B) 6 painters

Explanation:

Two painters can complete two rooms in two hours.So 18 rooms can be painted in 6 hrs by 6 painters

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3 11455
Q:

If two painters can complete two rooms in two hours, how many painters would it take to do 18 rooms in 6 hours?

A) 2 painters B) 6 painters
C) 4 painters D) None
 
Answer & Explanation Answer: B) 6 painters

Explanation:

Two painters can complete two rooms in two hours.So 18 rooms can be painted in 6 hrs by 6 painters

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1 4335
Q:

The difference between a two-digit number and the number obtained by interchanging the two digits is 63. Which is the smaller of the two numbers ?

A) 12 B) 15
C) 17 D) none of these answers can be determined
 
Answer & Explanation Answer: D) none of these answers can be determined

Explanation:

Let the ten's digit be x and unit's digit be y.

Then, (10x + y) - (10y + x) = 63  

=>  9 (x - y) = 63

=> x - y = 7.

Thus, none of the numbers can be deermined..

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5 13397
Q:

There are two numbers such that the sum of twice the first and thrice the second is 39, while the sum of thrice the first, and twice the second is 36. The larger of the two is :

A) 3 B) 6
C) 9 D) 12
 
Answer & Explanation Answer: C) 9

Explanation:

Let the numbers be x and y. Then, 2x + 3y = 39...(i)and 3x + 2y = 30 ...(ii)

On solving (i) and (ii), we get :  x = 6 and y = 9.

larger number = 9

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23 15289
Q:

The sum of the squares of two numbers is 3341 and the diference of their squares is 891. The numbers are :

A) 35 and 46 B) 35 and 50
C) 40 and 55 D) 45 and 60
 
Answer & Explanation Answer: A) 35 and 46

Explanation:

Let the numbers be x and y. Then,

 

x^2+y^2=3341......(1)

 

x^2-y^2=891......(2)

 

Adding (i) and (ii), we get : 2x^2=4232 or x^2= 2116 or x =46

 

Subtracting (ii) from (i), we get : 2y^2= 2450 or y^2 = 1225 or y = 35

 

So, the numbers are 35 and 46

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14 14286
Q:

Three times the first of three consecutive odd integers is 3 more than twice the third. The third integer is :

A) 12 B) 137
C) 14 D) 15
 
Answer & Explanation Answer: D) 15

Explanation:

Let the three integers be x, x + 2 and x + 4. Then, 3x = 2 (x + 4) + 3  <=> x = 11.

Third integer = x + 4 = 15.

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