Quantitative Aptitude - Arithmetic Ability Questions

Of the 5 numbers whose average is 78, the first is 2/11 times the sum of other 4. The first number is

A machine depreciates in value each year at the rate of 10% of its previous value. However, every second year there is some maintenance work so that in that particular year, depreciation is only 5% of its previous value. If at the end of the fourth year, the value of the machine stands at Rs 1,46,205, then find the value of machine at the start of the first year.

Two cars travel from city A to city B at a speed of 30 and 48 km/hr respectively. If one car takes 3 hours lesser time than the other car for the journey, then the distance between City A and City B is

A missile travels at 1206 km/h. How many metres does it travel in one second?

In ∆XYZ measure of angle Y is 90 deg. If sinX = 4/5, and XY = 6cm, then what is the length (in cm) of side YZ?

If ab+ba = -1, then the value of a2b-b2a is

sec2Acosec2A is equal to