The arithmetic mean of the following data is .

23, 17,20,19,21

If (a+b)=16 and a³+b³=1456, then what is the value of ab?

The ratio of two unequal sides of a rectangle is 1 : 2. If its perimeter is 24 cm, then the length of diagonal in cm is:

Directions: The bar graph given below shows the production (in ' 000 tones) of rice of a country for the year 2007 to 2011. Study the graph carefully and answer the question given below it.

The production of rice in the year 2011 is what percent of the production of rice in 2010?

If the difference between CI and SI for 3 years at the rate of 10% is Rs 31. Find the principle.

A, B, and C alone can do a work in 40 days ,120 days and 36 days respectively. A and B work together for 20 days and leave it incomplete. C carries on the work and complete it alone.  How many days did C take to complete the work?

The average weight of 5 persons sitting in a boat is 38 kg. The average weight of the boat and the persons sitting in the boat is 52 kg. What is the weight of the boat?

A contractor undertakes to finish a certain work in 124 days and employed 120 men. After 64 days, he found that he had already done 2/3 of the work. How many men can be discharged so that the work may finish in time ?