Quantitative Aptitude - Arithmetic Ability Questions

A man goes to a place on bicycle at speed of 16 km/hr and comes back at lower speed . If the average speed is 6.4 km/hr in total , then the return speed (in km/hr) is

A boat is sailing towards a lighthouse of height 20√3 m at a certain speed. The angle of elevation of the top of the lighthouse changes from 30° to 60° in 10 seconds. What is the time taken (in seconds) by the boat to reach the lighthouse from its initial position?

When 0.151515.....is converted into a fraction, then the result is

A certain sum of money becomes 4 times of itself in 30 years at a rate of simple interest. In how many years it will become double of itself at the same rate of simple interest?

If the time increases by 7 years, then simple interest increases by Rs 8400 on a sum of Rs 6000. What is the rate (in percentage) of interest per annum?

The area of a semicircle is 308 sq.cm. Calculate its perimeter (in cm)

If the population of a town increases by 25% in the first year and increases by 36% in the second year, then what is the average rate (in percentage)of increase in the population?

A kite is flying in the sky. The length of string between a point on the ground and kite is 420 m. The angle of elevation of string with the ground is 30 deg. Assuming that there is no slack in the string, then what is the height (in metres) of the kite?