Find the average of cubes of natural numbers from $1$ to $8$:

The sum of three consecutive numbers is $126$. Find the highest number-

1. $41$
2. $42$
3. $43$
4. $44$

How many times does the number $3$ occur in unit's place for numbers ranging from $1$ to $100$?

1. $20$
2. $11$
3. $10$
4. $19$

1 USD = Rs. 67.89. A money changer adds a margin of Rs. 1.11. What will be the cost of 150 USD ? 

1. Rs. 10,183
2. Rs. 10,350
3. Rs. 10,330
4. Rs. 10,450

Twice the difference between two numbers is equal to their sum. If one number is $15$, Find the other number.

1. $15$
2. $10$
3. $5$
4. $20$

Arrange the following in the descending order $\left(\sqrt{23}-\sqrt{21}), (\sqrt{19}-\sqrt{17}), (\sqrt{21}-\sqrt{19}\right)$.