The Ajmer express can move at 45 km./hr. without its rake and the speed is diminished by a constant that varies as the square root of the number of wagons attached. If it is known that with 9 wagons, the speed is 30 km./hr., what is the greatest number of wagons with which the train can just move?

The monthly salaries of A, B and C are in the ratio 2 : 3 : 5. If C's monthly salary is ₹ 12,000 more than that of A, then B's annual salary is 

Directions:Study the following table carefully to answer these questions:

Percentage of Marks obtained by six students in six subjects

What are the total marks obtained by ‘B’ in all the subjects together ?

With a 5 % discount on the cost of sugar, a buyer could purchase 2 kg. more sugar for ₹ 608. Original selling price of sugar is. 

The average age of 30 boys in a class is 15 years. One boy, aged 20 years, left the class, but two new boys came in his place whose age differs by 5 years. If the average age of all the boys now in the class becomes 15 years, the age of the younger newcomer is: 

A alone would take 6 hours more to complete the job than if both A and B would work together. When B worked alone he took 1.5 hours more to complete the job and A and B worked together. How much time they will take if they if they work together?

A sum of money is invested at 20 % compound interest (compounded annually). It would fetch 723 more if interest is compound half-yearly. The sum is –