The mean of 5 observations is 25. When a constant ‘x’ is added to each observation, the mean becomes 30. Find the value of x.

If $(343)^{y}$= 16807. Find the value of (y). 

Find the unit digit of 11 × 72 × 83?

The ratio of the age of Ajay and Atul is 4:5. After 5 years the ratio will be 5:6. Find the ratio of their age after 20 years.

Which of the following will completely divide 14,874?

The average age of four brothers is 20 years. When the age of their father is included, the average age increases by 20%. Find the age of the father.

The average age of 30 boys in a class is 15 years. 10 new boys are admitted to the class whose average age is 17 years. Find the average age of all the boys in the class.

Which of the following will completely divide 32112?

Simplify

$\frac{196\times 196-169\times 169}{5}$

The average of four consecutive even numbers is 11. Find the largest number.

Find the value of

$\left({25}^2-{24}^2\right)$

Find the unit digit of 6³⁶?

If a & b = $\left(\right. \frac{a}{2} + 2 b \left.\right)$(b + a). Find (4 & 2) + (2 & 1). 

Find the approximate value 

$\frac{0.2 + 0.3 + \sqrt{0.24}}{\sqrt{0.2} + \sqrt{0.3}}$ 

Which of the following will be the last digit of 8⁵¹³?