Aptitude

Question:
Two students appeared at an examination. One of them secured 9 marks more than the other and his marks was 56% of the sum of their marks. The marks obtained by them are:

[A].

39, 30

[B].

41, 32

[C].

42, 33

[D].

43, 34

Answer: Option C

Explanation:

Let their marks be (x + 9) and x.

Then, x + 9 =	56	(x + 9 + x)
	100

25(x + 9) = 14(2x + 9)

3x = 99

x = 33

So, their marks are 42 and 33.

Question: In a certain school, 20% of students are below 8 years of age. The number of students above 8 years of age is of the number of students of 8 years of age which is 48. What is the total number of students in the school?
[A].

72

[B].

80

[C].

120

[D].

150

Answer: Option E

Explanation:

Let the number of students be x. Then,

Number of students above 8 years of age = (100 – 20)% of x = 80% of x.

80% of x = 48 +	2	of 48
	3

	80	x = 80
	100

x = 100.

Video Explanation: https://youtu.be/yPfocU6DA2M

Question: In an election between two candidates, one got 55% of the total valid votes, 20% of the votes were invalid. If the total number of votes was 7500, the number of valid votes that the other candidate got, was:

[A].

2700

[B].

2900

[C].

3000

[D].

3100

Answer: Option A

Explanation:

Number of valid votes = 80% of 7500 = 6000.

Valid votes polled by other candidate = 45% of 6000

=		45	x 6000		= 2700.
		100

Question: A fruit seller had some apples. He sells 40% apples and still has 420 apples. Originally, he had:
[A].

588 apples

[B].

600 apples

[C].

672 apples

[D].

700 apples

Answer: Option D

Explanation:

Suppose originally he had x apples.

Then, (100 – 40)% of x = 420.

	60	x x = 420
	100

x =		420 x 100	= 700.
		60

Video Explanation: https://youtu.be/-Pv25Do3WwY

Question: A batsman scored 110 runs which included 3 boundaries and 8 sixes. What percent of his total score did he make by running between the wickets?
[A].

45%

[B].

45	5	%
	11

[C].

54	6	%
	11

[D].

55%

Answer: Option B

Explanation:

Number of runs made by running = 110 – (3 x 4 + 8 x 6)

= 110 – (60)

= 50.

Required percentage =		50	x 100	% = 45	5	%
		110			11

Video Explanation: https://youtu.be/X2zTnABqEHU

Question: Gauri went to the stationers and bought things worth Rs. 25, out of which 30 paise went on sales tax on taxable purchases. If the tax rate was 6%, then what was the cost of the tax free items?

[A].

Rs. 15

[B].

Rs. 15.70

[C].

Rs. 19.70

[D].

Rs. 20

Answer: Option C

Explanation:

Let the amount taxable purchases be Rs. x.

Then, 6% of x =	30
	100

x =		30	x	100	= 5.
		100		6

Cost of tax free items = Rs. [25 – (5 + 0.30)] = Rs. 19.70

Question:
What is the percentage error in the calculation?
[A].

34%

[B].

44%

[C].

54%

[D].

64%

Answer: Option D

Explanation:

Let the number be x.

Then, error =	5	x –	3	x =	16	x.
	3		5		15

Error% =		16x	x	3	x 100	% = 64%.
		15		5x

Question:
The population of a town increased from 1,75,000 to 2,62,500 in a decade. The average percent increase of population per year is:

[A].

4.37%

[B].

5%

[C].

6%

[D].

8.75%

Answer: Option B

Explanation:

Increase in 10 years = (262500 – 175000) = 87500.

Increase% =		87500	x 100	% = 50%.
		175000

Required average =		50	% = 5%.
		10

Question: Two numbers A and B are such that the sum of 5% of A and 4% of B is two-third of the sum of 6% of A and 8% of B. Find the ratio of A : B.
[A].

2 : 3

[B].

1 : 1

[C].

3 : 4

[D].

4 : 3

Answer: Option D

Explanation:

5% of A + 4% of B =	2	(6% of A + 8% of B)
	3

	5	A +	4	B	=	2		6	A +	8	B
	100		100			3		100		100

	1	A +	1	B	=	1	A +	4	B
	20		25			25		75

		1	–	1	A =		4	–	1	B
		20		25			75		25

	1	A =	1	B
	100		75

A	=	100	=	4	.
B		75		3

Required ratio = 4 : 3

Video Explanation: YouTube Video

Question: What percentage of numbers from 1 to 70 have 1 or 9 in the unit’s digit?
[A].

1

[B].

14

[C].

20

[D].

21

Answer: Option C

Explanation:

Clearly, the numbers which have 1 or 9 in the unit’s digit, have squares that end in the digit 1. Such numbers from 1 to 70 are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.

Number of such number =14

Required percentage =		14	x 100	% = 20%.
		70

Video Explanation: https://youtu.be/cBamI6iRNIA