China ke Chinese ne bhari udaan 1500 years AGO!

A plant expected to have an age of 1500 years is

In how many years 1 g of pure radium will be reduced to 1 milligram? The half-life of radium is 1,500 years.

The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is (a) 35 years (b) 40 years (c) 50 years (d) None of these