For the following questions answer them individually
In an exam, the average marks obtained by the students was found to be 60. After omission of computational errors, the average marks of some 100 candidates had to be changed from 60 to 30 and the average with respect to all the examinees came down to 45 marks. The total number of candidates who took the exam, was
The average pocket money of 3 friends A, B, C is `80 in a particular month. If B spends double and C spends triple of what A spends during that month and if the average of their unspent pocket money is `60, then A spends (in `)
An item when sold for `1,690 earned 30% profit on the cost price. Then the cost price is
A man purchased an article and sold it to B at a profit of 25% and B sold it to C at a loss of 10% and C paid `675 for it. For how much did A purchase it (in `)?
There is a rebate of 15%, if electric bills are paid in due time. A man enjoyed a rebate of `54 by paying the bill in time. What was his electric bill?
A sold a tape-recorder to B for `4,860 at a loss of 19%. Again B sold it to C at a price that would give A a profit of 17%. The gain of B is
Two trains starts from a place on two parallel tracks in the same direction .The speed of the trains are 45 km/hr and 40 km/hr respectively .The distance between the two trains after 45 minutes will be
The compound interest on a certain sum of money for 2 years at 10% per annum is `420. The simple interest on the same sum at the same rate and for the same time will be
The radius of a metallic cylinder is 3 cm and its height is 5 cm. It is melted and moulded into small cones, each of height 1 cm and base radius 1 mm. The number of such cones formed, is
A solid sphere of 6 cm diameter is melted and recast into 8 solid spheres of equal volume. The radius (in cm) of each small sphere is