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Question 151

WB Police SI 2024• Test

Two numbers are in the ratio 3 ∶ 5. If 10 is added with both the numbers, the ratio becomes 5 ∶ 7. What is the sum of two numbers?

  1. AOption (a)

    35

  2. BOption (b)

    40

  3. COption (c)

    8

  4. DOption (d)

    16

View answer & explanation

Correct answer

Answer: (b)B.

40

Why this answer is correct

Given:

Initial ratio of the two numbers = 3 ∶ 5

When 10 is added to both numbers, the ratio becomes 5 ∶ 7.

Formula Used:

Ratio equation: \(\frac{a+10}{b+10} = \frac{5}{7}\)

Calculation:

Let the numbers be 3x and 5x.

According to the problem:

\(\frac{3x + 10}{5x + 10} = \frac{5}{7}\)

Cross-multiplying gives:

⇒ 7(3x + 10) = 5(5x + 10)

⇒ 21x + 70 = 25x + 50

⇒ 21x - 25x = 50 - 70

⇒ -4x = -20

⇒ x = 5

The two numbers are:

First number = 3x = 3 × 5 = 15

Second number = 5x = 5 × 5 = 25

Sum of the two numbers = 15 + 25 = 40

The sum of the two numbers is 40.

Question 152

WB Police SI 2024• Test

In human body which hormone is secreted from a (alfa) cell of pancreas? 

  1. AOption (a)

    Insulin

  2. BOption (b)

    Glucagon

  3. COption (c)

    Oestrogen

  4. DOption (d)

    Progesterone

View answer & explanation

Correct answer

Answer: (b)B.

Glucagon

Why this answer is correct

The correct answer is Glucagon.

Key Points

  • Glucagon is a hormone secreted by the alpha cells of the pancreas.
  • It plays a crucial role in glucose metabolism and homeostasis.
  • Glucagon increases blood glucose levels by promoting gluconeogenesis and glycogenolysis in the liver.
  • It acts in opposition to insulin, which lowers blood glucose levels.
  • Glucagon is essential for maintaining normal blood sugar levels, especially during fasting or between meals.

Additional Information

  • Insulin, another pancreatic hormone, is secreted by the beta cells and helps lower blood sugar levels by facilitating cellular glucose uptake.
  • The pancreas also secretes other hormones:
  • Somatostatin from delta cells, which regulates the secretion of both insulin and glucagon.
  • Pancreatic polypeptide from PP cells, which helps regulate pancreatic secretions and gastrointestinal motility.

Question 153

WB Police SI 2024• Test

There is 20 litres milk in a container. 4 litres milk is withdrawn and substituted by 4 litres of water. The same process is repeated again. How many litres of milk will be left?

  1. AOption (a)

    13.8

  2. BOption (b)

    12.4

  3. COption (c)

    13.2

  4. DOption (d)

    12.8

View answer & explanation

Correct answer

Answer: (d)D.

12.8

Why this answer is correct

Given:

Initial milk in the container = 20 litres

Milk withdrawn in each step = 4 litres

Water added in each step = 4 litres

Process repeated = 2 times

Formula Used:

Remaining milk after each step = \(Initial milk × (1 - \frac{milk\ withdrawn}{total\ liquid}) \)

Calculation:

Initial milk = 20 litres

Milk withdrawn = 4 litres

Remaining milk = \(20 × (1 - \frac{4}{20})\)

⇒ Remaining milk = \(20 × \frac{16}{20}\)

⇒ Remaining milk = 16 litres

Initial milk = 16 litres

Milk withdrawn = 4 litres

Total liquid after adding water = 20 litres

Remaining milk = \(16 × (1 - \frac{4}{20})\)

⇒ Remaining milk = \(16 × \frac{16}{20}\)

⇒ Remaining milk = 12.8 litres

There will be 12.8 litres of milk left after the process is repeated twice.

Question 154

WB Police SI 2024• Test

The sum of marks obtained by Arun in English and Mathematics is 170 and the difference is 10. What is the ratio of marks obtained by Arun in English and Mathematics?

  1. AOption (a)

    9 ∶ 8

  2. BOption (b)

    9 ∶ 7

  3. COption (c)

    7 ∶ 8

  4. DOption (d)

    8 ∶ 7

View answer & explanation

Correct answer

Answer: (a)A.

9 ∶ 8

Why this answer is correct

Given:

The sum of marks obtained by Arun in English and Mathematics is 170.

The difference in marks obtained by Arun in English and Mathematics is 10.

Formula Used:

Let the marks in English be E and in Mathematics be M .

From the given conditions:

E + M = 170      ......(1)

E - M = 10     ......(2)

Calculation:

Adding equation (1) and (2):

⇒ (E + M) + (E - M) = 170 + 10

⇒ 2E = 180

⇒ E = 90

Substituting the value of E in equation (1):

⇒ 90 + M = 170

⇒ M = 80

Now, the ratio of marks in English to Mathematics is:

⇒ E : M = 90 : 80

⇒ 9 : 8

The ratio of marks obtained by Arun in English and Mathematics is 9 ∶ 8.

Question 155

WB Police SI 2024• Test

Which portion of human brain maintains the body balance ?

  1. AOption (a)

    Cerebellum

  2. BOption (b)

    Medulla Oblongata

  3. COption (c)

    Thalamus

  4. DOption (d)

    Mid Brain

View answer & explanation

Correct answer

Answer: (a)A.

Cerebellum

Why this answer is correct

The correct answer is Cerebellum.

Key Points

  • The Cerebellum is a crucial part of the brain that plays a significant role in maintaining body balance and coordination.
  • It is located at the back of the brain, underneath the occipital lobes of the cerebral cortex.
  • The cerebellum is responsible for fine-tuning motor activities and ensuring smooth, balanced muscular activity.
  • It also helps in maintaining posture and equilibrium, making it essential for everyday activities such as walking, running, and other physical movements.

Additional Information

  • The Medulla Oblongata is responsible for regulating vital functions such as heartbeat and breathing.
  • The Thalamus acts as a relay station for transmitting sensory and motor signals to the cerebral cortex.
  • The Mid Brain is involved in functions such as vision, hearing, eye movement, and body movement.

Question 156

WB Police SI 2024• Test

Which of the following figures will replace the "?" mark to continue the pattern?

  1. AOption (a)

  2. BOption (b)

  3. COption (c)

  4. DOption (d)

View answer & explanation

Correct answer

Answer: (d)D.

Why this answer is correct

The logic followed here is :

Hence the correct answer is Option 4.

Question 157

WB Police SI 2024• Test

In standard temperature and pressure which of the following is not an amorphous?

  1. AOption (a)

    Chalk

  2. BOption (b)

    Coal tar

  3. COption (c)

    Wood

  4. DOption (d)

    Common Salt

View answer & explanation

Correct answer

Answer: (d)D.

Common Salt

Why this answer is correct

The correct answer is Common Salt.

Key Points

  • Common salt (sodium chloride) is a crystalline solid.
  • Amorphous solids are solids that do not have a long-range order of atoms.
  • Examples of amorphous solids include substances like chalk, coal tar, and wood.
  • Common salt has a well-defined crystalline structure, unlike amorphous solids.

Additional Information

  • Amorphous solids have a disordered arrangement of atoms or molecules.
  • Crystalline solids have a highly ordered arrangement of atoms or molecules, which contributes to their unique physical properties.
  • Common salt is an example of a crystalline solid, characterized by its regular and repeating pattern of sodium and chloride ions.

Question 158

WB Police SI 2024• Test

If '×' stands for '+', '<' stands for '-', '+' stands for '÷', '>' stands for '×', '-' stands for '=', '÷' stands for '>' and '=' stands for '<', state which of the following is true.

  1. AOption (a)

    3 × 4 > 2 - 9 + 3 < 3 

  2. BOption (b)

    5 × 3 < 3 ÷ 8 + 4 × 4

  3. COption (c)

    3 × 2 < 4 ÷ 16 > 2 + 4

  4. DOption (d)

    5 > 8 + 4 = 10 < 4 × 8 

View answer & explanation

Correct answer

Answer: (d)D.

5 > 8 + 4 = 10 < 4 × 8 

Why this answer is correct

According to the given information,

Code×<+>-÷=
Stands for+-÷×=><

Let's check each option,

1) 3 × 4 > 2 - 9 + 3 < 3 

→ 3 + 4 × 2 = 9 ÷ 3 - 3 

→ 3 + 4 × 2 = 3 - 3

→ 3 + 8 = 3 - 3

→ 11 = 3 - 3

→ 11 = 0 ⇒ This is not true.

2) 5 × 3 < 3 ÷ 8 + 4 × 4

→ 5 + 3 - 3 > 8 ÷ 4 + 4

→ 5 + 3 - 3 > 2 + 4

→ 8 - 3 > 6

→ 5 > 6 ⇒ This is not true.

3) 3 × 2 < 4 ÷ 16 > 2 + 4 

→ 3 + 2 - 4 > 16 × 2 ÷ 4 

→ 3 + 2 - 4 > 16 × 1/2 

→ 3 + 2 - 4 > 8

→ 5 - 4 > 8

→ 1 > 8 ⇒ This is not true.

4) 5 > 8 + 4 = 10 < 4 × 8 

→ 5 × 8 ÷ 4 < 10 - 4 + 8 

→ 5 × 2 < 10 - 4 + 8 

→ 10 < 10 - 4 + 8 

→ 10 < 18 - 4

→ 10 < 14 ⇒ This is true.

Hence, the correct answer is "5 > 8 + 4 = 10 < 4 × 8".

Question 159

WB Police SI 2024• Test

A and B were moving in cycles in same direction at a speed of 8 metres / sec and 5 metres / sec respectively. At a given time B was 180 metres ahead of A. In next 70 seconds what shall be the distance between them (in metre)?

  1. AOption (a)

    50

  2. BOption (b)

    60

  3. COption (c)

    30

  4. DOption (d)

    40

View answer & explanation

Correct answer

Answer: (c)C.

30

Why this answer is correct

Given:

Speed of A = 8 metres/second

Speed of B = 5 metres/second

Initial distance between A and B = 180 metres

Time = 70 seconds

Formula Used:

Relative Speed = Speed of A - Speed of B

Distance covered = Relative Speed × Time

New Distance between A and B = Initial Distance - Distance covered

Calculation:

Relative Speed = 8 - 5

Relative Speed = 3 metres/second

Distance covered in 70 seconds = 3 × 70

⇒ Distance covered = 210 metres

New Distance between A and B = 210 - 180

⇒ New Distance = 30 metres

The distance between A and B after 70 seconds is 30 metres.

Question 160

WB Police SI 2024• Test

The country Madagascar is situated in which continent ?

  1. AOption (a)

    North America

  2. BOption (b)

    South America

  3. COption (c)

    Asia

  4. DOption (d)

    Africa

View answer & explanation

Correct answer

Answer: (d)D.

Africa

Why this answer is correct

The correct answer is Africa.

Key Points

  • Madagascar is located in the Indian Ocean, off the southeastern coast of Africa.
  • It is the fourth largest island in the world and is part of the African continent.
  • The capital city of Madagascar is Antananarivo.
  • Madagascar is known for its unique biodiversity and is home to many species that are not found anywhere else in the world.

Additional Information

  • Madagascar separated from the Indian subcontinent around 88 million years ago, allowing its flora and fauna to evolve in relative isolation.
  • The island is famous for its lemurs, baobab trees, and unique ecosystems.
  • Due to its isolation, Madagascar has a high rate of endemism, with many species that are found nowhere else on Earth.