The simple interest on a sum for 5 years is 3/5 th of the sum. The rate of interest per annum is:

A certain number of men complete a piece of work in 60 days. If there were 8 men more, the work can be finished in 10 days less. The number of men originally is:

A fruit seller buys 100 kg of superior variety of mangoes at INR 45 per kg and 200 kgs of inferior variety at INR 40 per kg and sells all the mangoes at INR 45 per kg. The progit percentage of the fruit seller is:

The average age of 30 students is 20 years and average age of 20 other students is 30 years. The average age of total number of students is :

If the ratio of areas of two circles is 4:9, then the ratio of their circumference will be:

The radius of a circle is increased by 10%. the percentage increase of its area is: