The external and the internal radii of a hollow right circular cylinder of height 15 cm are 6.75 cm and 5.25 cm respectively. If it is melted to form a solid cylinder of height half of the orignal cylinder, then the radius of the solid cylinder is
Ravichandran Ashwin became the fastest player in the world (in terms of number of test matches) to get 300 wickets in test cricket in November 2017. Whose record did Ashwin break?