Two years ago, a man’s age was three times the square of his son’s age. In three years time, his age will be four times his son’s age. Find their present ages.

Ashish goes to his friends house which is 12 km away from his house. He covers half of the distance at a speed of x km per hour and the remaining at (x + 2) km per hour. If he takes 2 hrs 30 min. to cover the whole distance, find the value of x.

A train covers a distance of 600 km at x km/hr. Had the speed been (x + 20) km/hr, the time taken to cover the same distance would have been reduced by 5 hours. Write down an equation in x and solve it to evaluate x.

A train covers a distance of 780 km at x km/hr. Had the speed been (x − 5) km/hr, the time taken to cover the same distance would have been increased by 1 hour. Write down an equation in x and solve it to evaluate x.