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
Q:

A person in a bet 40 shots taken. 50p for a hit, 10p for a miss.(he have to give). Finally he has Rs.5. How many hits he have ?

A) 15 B) 20
C) 25 D) 30
 
Answer & Explanation Answer: A) 15

Explanation:

Let number of hit shots be 'X'
Let number of miss shots be 'Y'
Given X + Y = 40....(1)
50X - 10Y = 500.....(2)
Solving 1 and 2, we get
X = 15 and Y = 25
Therefore, number of hits = 15

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2 4955
Q:

Srinivas bought 10 cycles for Rs. 1,750 each. He sold 4 cycles for Rs 8,400, 3 for Rs 1900 each . At what price should he sell the remaining cycles so as to earn an average profit of Rs 320 per cycle ?

A) Rs. 1580 B) Rs. 2200
C) Rs. 1785 D) Rs. 1950
 
Answer & Explanation Answer: B) Rs. 2200

Explanation:

He sold 4 cycles for Rs. 8400
[It means each cycle price is Rs. 2100]
And again he sold 3 cycles for Rs. 1900 each
If he want to gain avg profit on each cycle is Rs. 320 per cycle.
So profit for 10 cycles is @ Rs.320 is,
10 x 320 = Rs. 3200
He already got Rs. 1850 profit by selling 7 cycles.
Now, remaining amount is 3200 - 1850 = 1350
So from remaining 3 cycles we want to get Rs. 1350 profit ,
1350/3 = 450
so he must sell remaining 3 cycles at Rs. 2200 each one.

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7 10977
Q:

A person walking 6/7 of his usual rate is 30 minutes late. What is his usual time ?

A) 2 hrs 50 min B) 3 hrs 25 min
C) 3 hrs D) 2 hrs 5 min
 
Answer & Explanation Answer: C) 3 hrs

Explanation:

Let t be the usual time. If the usual rate is 1 unit, then the unusual rate is 6/7.
Balance by the distance,
1 x t = (6/7)(t + 30)
7t = 6(t + 30)
we get t as,
t = 180 minutes = 3 hrs.

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2 4187
Q:

The sum of one-half, one-third and one-fourth of a number exceeds the number by 22. The number is

A) 264 B) 284
C) 215 D) 302
 
Answer & Explanation Answer: A) 264

Explanation:

Let the number be 'x'. Then, from given data

x/2 + x/3 + x/4 = x+22
13x/12 = x+22
x = 264

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4 6441
Q:

There are 15 lines in plane. How many intersections (Maximum) can be made ?

A) 55 B) 105
C) 215 D) 148
 
Answer & Explanation Answer: B) 105

Explanation:

First line will cut all other 14, similarly second will cut 13, and so on
Total = 14+13+12+11+10+9+8+7+6+5+4+3+2+1 = 105.

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6 4203
Q:

If 78K928L is divisible by 6, then which of the following can Q and R take ?

A) K=2 & L=3 B) K=1 & L=4
C) K=1 & L=2 D) K=3 & L=3
 
Answer & Explanation Answer: B) K=1 & L=4

Explanation:

As per divisibility rule a number is divisible by 6 means it should be divisible by 2 and 3

case 1 : the divisibility rule for 2 is the number should be end with even number
in this case R =2 & R=4


case 2 : The divisibility rule for 3 is the sum of numbers should be divisible by 3
so if we take option (2) Q=1 & R=4 the sum is 39
if we take option (3) Q=1 & R=2 the sum is 37

So Option (2) is correct 39 is divided by 3

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4 3630
Q:

If a number 72k23l is divisible by 88. Then find value of k and l ?

A) k=8 & l=2 B) k=7 & l=2
C) k=8 & l=3 D) k=7 & l=1
 
Answer & Explanation Answer: B) k=7 & l=2

Explanation:

If a number to be divisile by 88, it should be divisible by both "8" and "11"

Check for '8' :
For a number to be divisible by "8", the last 3-digit should be divisible by "8"
Here 72x23y --> last 3-digit is '23y'
So y=2 [ (i.e) 232 is absolutely divisible by "8"]

Chech for '11' :
For a number to be divisible by "11" , sum of odd digits - sum of even digits should be divisible by "11"
(7 + x + 3) - (2 + 2 + y)
(7 + x + 3) - (2 + 2 + 2)
(10 + x) - 6 should be divisible by "11"
for x = 7
=> 17 - 6 = 11 [ which is absolutely divisible by "11"]

So x = 7 , y= 2.

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10 12237
Q:

The product of two positive numbers is p. If each of the numbers is increased by 2, the new product is how much greater than twice the sum of the two original numbers ?

A) p times B) 2p times
C) (p + 4) times D) (2p + 3) times
 
Answer & Explanation Answer: C) (p + 4) times

Explanation:

Let the two no's be a and b;
Given product of the no's is p = ab;
If the each nos is increased by 2 then the new product will be
(a+2)(b+2) = ab + 2a + 2b + 4
= ab + 2(a+b) + 4
= p + 2(a+b) + 4
Hence the new product is (p+4) times greater than twice the sum of the two original numbers.

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11 9148