Quantitative Aptitude - Arithmetic Ability Questions

If the average age of 20 students in Class-I is 10 years and average age of 25 students in Class II is 12 years, find the average age (in years) of all students.

If the edge of a cube is increased by 3 cm, the volume will increase by 657 cub.cm. What then is the original length of each edge of the cube?

If x=8+215, then what is the value of x+1x?

Divide 13,680 in three parts such that 1st part is 3/5th of the third part and the ratio between 2nd and 3rd part is 4:7. How much is the first part?

If a merchant offers a discount of 20% on the list price, then he makes a loss of 10%. What % profit or % loss will she make if he sells at a discount of 5% of the list price?

The cost of leveling a triangular piece of land whose sides are 72 m. 30 m and 78 in respectively at the rate of 20 paisa per square metre is:

When a number is increased by 38, it becomes 119% of itself. What is the number?

The standard deviation of the set {10, 11, 9, 11, 9} is