Aptitude | Numbers

How many prime numbers are less than 50 ?

Byadmin July 18, 2022

Question:
How many prime numbers are less than 50 ?

[A].

[B].

[C].

[D].

Answer: Option B

Explanation:

Prime numbers less than 50 are:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47

Their number is 15

Alligation Or Mixture | Aptitude

Tea worth Rs. 126 per kg and Rs. 135 per kg are mixed with a third variety in the ratio 1 : 1 : 2. If the mixture is worth Rs. 153 per kg, the price of the third variety per kg will be:

Question: Tea worth Rs. 126 per kg and Rs. 135 per kg are mixed with a third variety in the ratio 1 : 1 : 2. If the mixture is worth Rs. 153 per kg, the price of the third variety per kg will be:
[A].

Rs. 169.50
[B].
Rs. 170
[C].
Rs. 175.50
[D].
Rs. 180

Answer: Option C

Explanation:

Since first and second varieties are mixed in equal proportions.

So, their average price = Rs. 126 + 135 = Rs. 130.50

2

So, the mixture is formed by mixing two varieties, one at Rs. 130.50 per kg and the other at say, Rs. x per kg in the ratio 2 : 2, i.e., 1 : 1. We have to find x.

By the rule of alligation, we have:

Cost of 1 kg of 1st kind
Cost of 1 kg tea of 2nd kind

Rs. 130.50 Mean Price
Rs. 153 Rs. x

(x – 153) 22.50

x – 153 = 1

22.50

x – 153 = 22.50

x = 175.50

Read More Tea worth Rs. 126 per kg and Rs. 135 per kg are mixed with a third variety in the ratio 1 : 1 : 2. If the mixture is worth Rs. 153 per kg, the price of the third variety per kg will be:
Aptitude | Time And Distance

A man covered a certain distance at some speed. Had he moved 3 kmph faster, he would have taken 40 minutes less. If he had moved 2 kmph slower, he would have taken 40 minutes more. The distance (in km) is:

Question:
A man covered a certain distance at some speed. Had he moved 3 kmph faster, he would have taken 40 minutes less. If he had moved 2 kmph slower, he would have taken 40 minutes more. The distance (in km) is:

[A].

35
[B].

36 2

3

[C].

37 1

2

[D].
40

Answer: Option D

Explanation:

Let distance = x km and usual rate = y kmph.

Then, x – x = 40 2y(y + 3) = 9x ….(i)

y y + 3 60

And, x – x = 40 y(y – 2) = 3x ….(ii)

y -2 y 60

On dividing (i) by (ii), we get: x = 40.

Read More A man covered a certain distance at some speed. Had he moved 3 kmph faster, he would have taken 40 minutes less. If he had moved 2 kmph slower, he would have taken 40 minutes more. The distance (in km) is:
Aptitude | Problems on Numbers

The difference between a two-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1 : 2 ?

Question:
The difference between a two-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1 : 2 ?

[A].

4
[B].
8
[C].
16
[D].
None of these

Answer: Option B

Explanation:

Since the number is greater than the number obtained on reversing the digits, so the ten’s digit is greater than the unit’s digit.

Let ten’s and unit’s digits be 2x and x respectively.

Then, (10 x 2x + x) – (10x + 2x) = 36

9x = 36

x = 4.

Required difference = (2x + x) – (2x – x) = 2x = 8.

Read More The difference between a two-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1 : 2 ?
Basic Maths Mcqs | Boats and Streams | Mathematics Mcqs

The speed at which a man can row a boat in still water is 15 kmph. If he rows downstream, where the speed of current is 3 kmph, what time will he take to cover 60 metres?

The speed at which a man can row a boat in still water is 15 kmph. If he rows downstream, where the speed of current is 3 kmph, what time will he take to cover 60 metres?

A. 10 seconds
B. 15 seconds
C. 20 seconds
D. 12 seconds
E. None of these
Explanation:
Speed of the boat downstream = 15 + 3 = 18 kmph
= 18 * 5/18 = 5 m/s
Hence time taken to cover 60 m = 60/5 = 12 seconds.

Read More The speed at which a man can row a boat in still water is 15 kmph. If he rows downstream, where the speed of current is 3 kmph, what time will he take to cover 60 metres?
Aptitude | Pipes And Cistern

A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same time during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is:

Question:
A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same time during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is:

[A].

6 hours
[B].
10 hours
[C].
15 hours
[D].
30 hours

Answer: Option C

Explanation:

Suppose, first pipe alone takes x hours to fill the tank .

Then, second and third pipes will take (x -5) and (x – 9) hours respectively to fill the tank.

1 + 1 = 1

x (x – 5) (x – 9)

x – 5 + x = 1

x(x – 5) (x – 9)

(2x – 5)(x – 9) = x(x – 5)

x2 – 18x + 45 = 0

(x – 15)(x – 3) = 0

x = 15. [neglecting x = 3]

Read More A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same time during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is:
Aptitude | Profit And Loss

100 oranges are bought at the rate of Rs. 350 and sold at the rate of Rs. 48 per dozen. The percentage of profit or loss is:

Question: 100 oranges are bought at the rate of Rs. 350 and sold at the rate of Rs. 48 per dozen. The percentage of profit or loss is:
[A].

14 2 % gain

7

[B].
15% gain
[C].

14 2 % loss

7

[D].
15 % loss

Answer: Option A

Explanation:

C.P. of 1 orange = Rs. 350 = Rs. 3.50

100

S.P. of 1 orange = Rs. 48 = Rs. 4

12

Gain% = 0.50 x 100 % = 100 % = 14 2 %

3.50 7 7

Read More 100 oranges are bought at the rate of Rs. 350 and sold at the rate of Rs. 48 per dozen. The percentage of profit or loss is:

So, their average price = Rs.		126 + 135		= Rs. 130.50
		2

Cost of 1 kg of 1st kind Cost of 1 kg tea of 2nd kind
Rs. 130.50	Mean Price Rs. 153	Rs. x
(x – 153)		22.50

	x – 153	= 1
	22.50

Then,	x	–	x	=	40	2y(y + 3) = 9x ….(i)
	y		y + 3		60

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