RRB NTPC Cbt Online Practice Bits Set - 21

Quantity
1. The average age of four boys. five years ago was 9 years. On including a new boy, the present average age of all the five is 15 years. The present age of the new boy is
(1) 14 years 
(2) 6 years
(3) 15 years 
(4) 19 years

2. The cost of a piece of diamond varies with the square of its weight. A diamond of Rs. 5,184 value is cut into 3 pieces whose weights are in the ratio l : 2 : 3. Find the loss involved in the cutting.
(1) Rs. 3,068 
(2) Rs. 3,088
(3) Rs. 3.175 
(4) Rs. 3,168

3. A discount of 30% on the marked price of a toy reduces its selling price by Rs. 30. What is the new selling price (in Rs.)?
(1) 70  
(2) 21 
(3) 130  
(4) 100

4. Pipe A alone can fill a tank in 8 hours. Pipe B alone can fill it in 6 hours. If both the pipes are opened and after 2 hours pipe A is closed, then the other pipe will fill the tank in
(1) 6 hours  
(2) 3.5 hours
(3) 4 hours 
(4) 2 .5 hours


5. The population of a town is 15000. If the number of males increases by 8% and that of females by 10%, then the population would increase to 16300. Find the number of females in the town.
(1) 4000  
(2) 6000
(3) 3000 
(4) 5000

ANSWERS with Expiation:  
1. (4) Sum of the present ages of four boys = 9 * 4 + 20 = 56 years
Sum of the present ages of five boys = 15 * 5 = 75 years
so Present age of new boy = 75 – 56 = 19 years

2. (4) If the weight of  a piece of diamond be 6 x units, then Original price α(6x)^2 = 36kx^2
so 36.kx^2 = 5184 ………(i) Again, New price = k(x^2 + 4x^2 + 9x^2)
= 14kx^2 = (14 * 5184)/36 = Rs. 2016 so Loss = 5184 – 2016
= Rs. 3168

3. (1) 30% = Rs. 30 so 100% = Rs. 100
New S.P. = 100 -30 = Rs. 70

4. (4) Part of the tank filled by both pipes in two hours
= 2 (1/8 + 1/6) = 2(3 + 4)/24 = 7/12 Remaining part = 1 – 7/12 = 5/12
Time taken by B in filling the remaining part = 5/12 * 6 = 5/2 = 2 1/2 hours

5. (4) If the number of females be x, then number of males = 15000 – x so x * 10/100 + (15000 –x) * 8/100
= 16300 – 15000 = 10x + 120000 – 8x
= 1300 * 100 => 2x = 130000 – 120000 = 10000 =>x  = 5000

Reasoning

6.‘A’ man starts from a point and walks 2 km towards North, turns towards his right and walks 2 km, turns right again and walks. What is the direction now he is facing?
(1) South   
(2) South-East
(3) North  
(4) West

7. Kamu walks 5 kms straight from her house towards west then turns right and walks 3 kms. There-after she takes left turn and walks 2 km. further, she turns left and walks 3 km. Finally, she turns right and walks 3 kms. In what direction she is now from her house?
(1) West  
(2) North
(3) South  
(4) East

8. Amit travelled 15 kms. East-ward, then turned left and travelled 5 kms, then turned left and travelled 15 kms. Hose far was Amit from the starting point?
(1) 30 kms.   
(2) 35 kms.
(3) 15 kms.  
(4) 5 kms.

9. At 12.30 the hour hand of a clock faces North and the minute hand faces South. At 2.45 the minute had will be in which direction?
(1) North-West  
(2) West
(3) South-East  
(4) East

10. Mamatha walks 14 metres towards west, then turns to her right and walks 14 metres and then turns to her left and walks 10 metres. Again turning to her left she walks 14 metres. What is the shortest distance (in metres) between her starting point and her present position?
(1) 38 m  
(2) 28 m
(3) 24 m  
(4) 10 m

Answers:

6.1

7.1

8.4

9.2

10.3

General Knowledge

1.The casual organism of polio is?
A)    A worm
B)    A bacteria
C)    A fungi
D)    A virus
Answer: D

2. Which of the following symbiotic associations forms a lichen?
A)    An algae and a fungus
B)    An algae and a bryophyte
C)    A bacterium and a fungus
D)    A bacterium and a gymnosperm
Answer: A

3. Whose experiment proved that the  speed of light was always the same?
A)    Isobar
B)    Iso electronic
C)    Isotopes
D)    Isotones
Answer: C

4.Radioactive isotope of hydrogen is?
A)    Protium
B)    Deuter
C)    Tritium
D)    All
Answer: C

5.Which one of the following is NOT a constituent of human development index(HDI) ?
A)    Per capita income
B)    Life expetancy at birth
C)    Gross enrolment rate
D)    Health and nutrition
Answer: C

6.Which if the following is a cool current?
A)    Tides
B)    Waves
C)    Current
D)    Tsunami
Answer: A

7.The tides are primarily caused by?
A)    Gravitational forces of the moon
B)    Gravitational force of the sun
C)    Gravitational forces of the earth
D)    None of these
Answer: A

8.National agricultural insurance scheme replacing comprehensive crop insurance scheme was introduced in the year?
A)    1997
B)    1998
C)    1999
D)    2000
Answer: C

9.The caves and rock-cut temples at ellora are?
A)    Hindu and buddhist
B)    Buddhist and jain
C)    Hindu and jain
D)    Hindu, buddhist and jain
Answer: D

10.Which article of indian constitution enumerates fundamental duties of indian citizens?
A)    Article 50-A
B)    Article 50-b
C)    Article 51-A
D)    Article 51-B
Answer: C

RRB NTPC Cbt Online Practice Bits Set - 21 RRB NTPC Cbt Online Practice Bits Set - 21 Reviewed by SSC-IBPS on 19:16:00 Rating: 5
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