With uniform speed,a car covers  a distance in 8 hours.Had the speed been increased by 4km/hr,the same distancec could have been covered in 7 hours 30 minutes.What is the distance covered?

In a flight of 600km ,an aircraft was slowed down due to bad weather.Its average speed for the trip was reduced by 200km/hr and the time of flight increased by 30 minutes.The duration of the flight is

The efficiency of P is twice that of Q,whereas efficiency of P and Q together is three times that of R.If P,Q and R work together on a job,in what ratio should they share their earnings?

For which value of k does the pair of equations x²-y²=0 and (x-k)²+y²=1 yield a unique positive solution of x?√

Two persons A and B start walking simultanoeusly from two places c km apart and walk in the same direction.If A travels at the rate of p km/hr and B travels at the rate of q km/hr ,then A has travelled before he overtakes B at a distance of

A car travels the first one-third of a distance with a speed of 10km/hr,the next one-third distancewith a speed of 20km/hr and the last one-third distance with a  speed of 60km/hr.The average speed of the car for the whole journey is