On checking option D

121 ÷ 11 + 54 – 9 × 3 = 128

After interchanging the signs

121 – 11 + 54 ÷ 9 × 3 = 128

121 – 11 + 6 X 3 = 128

121 – 11 + 18 = 128

110 + 18 = 128

128 = 128

After changing ÷ and – above equation is satisfied.

Hence, option D is the correct answer.

According to the question,

If we interchange – and ÷ the above equation becomes correct.

15 ÷ 3 + 10 – 5 × 2 (Applying BODMAS)

→ 5 + 10 – 10

→ 15 – 10

→ 5

Hence, option B is the correct answer.

Correct order:-

Slave dynasty (1206-1290)

Tughlaq dynasty (1320-1414)

Sayyid dynasty (1414-1450)

Lodhi dynasty (1451-1526)

Mughal dynasty (1526)

The correct order is B (1,4,2,3,5)

Hence, option B is the correct answer.

Formula: 

⇒  (1/2)[(198 -196)² + (196 - 197)² + (197 - 198)²]

⇒ (1/2)[4 + 1 + 1] = 3

Given,

x + 1/x = 7

By squaring both sides,

⇒ x² + 2 + 1/x²= 49

Subtract 4 from both sides,

⇒ x² – 2 + 1/x²= 45

⇒ (x – 1/x)² = 45

⇒ x – 1/x = 3√5

Now, required,

x² – 1/x²= (x + 1/x)( x – 1/x)

= 7 × 3√5 = 21√5

* Junagarh caves are situated in Junagarh district of Gujarat.

* There are mainly Buddhist caves.

* The presence of “Upper Kot” is the unique feature of these caves.

• The book ‘what young india wants’ is written by Chetan Bhagat.

• It is basically a compilation of his speeches and essays focusing on Indian Society, politics and the youth.

• The pituitary gland is a small pea-sized gland that plays a major role in regulating vital body functions and general wellbeing.

• It is referred to as the body's 'master gland' because it controls the activity of most other hormone-secreting glands.

• The pituitary gland is called “master gland” because its hormones control other parts of the endocrine system, namely the thyroid gland, adrenal glands, ovaries, and testes.

• The outer most covering of the human heart is Pericardium.
• The pericardium is a double-walled sac containing the heart and the roots of the great vessels.