7
Q:

The difference between a positive proper fraction and its reciprocal is 9 / 20. Then the fraction is :

A) 3/5 B) 3/10
C) 4/5 D) 5/4

Answer:   C) 4/5



Explanation:

Let the required fraction be x. Then, (1 / x )- x = 9/20
1 - x^(2) / x = 9 / 20  =>  20 - 20 * x^(2) = 9 * x.
20 * x^(2) + 9 *x - 20 = 0.
=> (4 * x + 5) (5 * x - 4) = 0.
=> x = 4 / 5.

Q:

How many numbers up to 300 and 700 are divisible by 2, 3 and 7 both together ?

A) 7 B) 9
C) 11 D) 5
 
Answer & Explanation Answer: B) 9

Explanation:

LCM of 2, 3, 7 is 42.

=> (700 – 300)/42 = 9  22/42 => 9 Numbers.

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3 148
Q:

In a triangle ABC, angle 'a' is the smallest one & A+7B = 112. Find the range of value 'c' ?

A) 138 to 164 B) 125 to 147
C) 148 to 158 D) 152 to 164
 
Answer & Explanation Answer: D) 152 to 164

Explanation:

A+7B=112

it is clear that A = 14, then it becomes A>=B, but A is smallest angle) given
so, range of A is 0.0001 to 13.9999 ( I am taking upto 4 decimal places)
so, range of B becomes 14 to 16 ( after rounding off to 4 decimal places)
so, range of C becomes 152 to 164 ( after rounding off to 4 decimal places)

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3 157
Q:

What will come in place of the question mark (?) in the following questions ?

22% of ? + 166.64 = 340 

A) 788 B) 786
C) 784 D) 792
 
Answer & Explanation Answer: A) 788

Explanation:

(kx22)/100 = 340 - 166.64 = 173.36
k = (173.36 x 100)/22
k = 788

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2 193
Q:

The sum of the digits of a two-digits number is 10,while when the digits are reversed, the number decreases by 54. Find the changed number ?

A) 28 B) 19
C) 37 D) 46
 
Answer & Explanation Answer: A) 28

Explanation:

Let the original number is 82 i.e 8 + 2 = 10 and when the digits are reversed i.e 28
The difference is 82 - 28 = 54 i.e, the number is decreased by 54.

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2 190
Q:

About 4 out of 5 students are left handed. If there are totally 40 students in an class. How many would be left handed ?

A) 40 B) 45
C) 32 D) 30
 
Answer & Explanation Answer: C) 32

Explanation:

Probability of left handed = 4/5
total student = 40
total left handed = 40 x(4/5)
= 32

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4 163