Quantitative Aptitude - Arithmetic Ability Questions

If √(1+tan2A) = x, then the value of x is

In a class of 56 students there are 28 girls. The average weight of these girls is 46 kg and average weight of the full class is 51 kgs. What is the average weight of the boys of the class?

The total surface area of a hemisphere is 4158 cm2. Find its diameter (in cm).

50 litre mixture of water and alcohol contains 10% alcohol. How much more alcohol must be added to make the strength of alcohol 40% in the new mixture?

The ratio between the speeds of two buses is 11:9. If the second bus runs 270 kms in 15 hours, then the speed of the first bus is?

10 persons can do a job in X days. If 20 persons with twice the efficiency can do the same job in 5 days, then find the value of X?

The diagonal of a cube is 192 cm. Its volume in cm3 will be 

Find the difference between place value and face value of 7 in 589573212.