Question
Obtain the chain base index number from the fixed base index nuimbers given below with the year $2007-08$ a the base year for the wholesale prices of machines and equipments :
| year | $2008-09$ | $2009-10$ | $2010-11$ | $2011-12$ | $2012-13$ |
| Index number of machines and equipments | $117.4$ | $118$ | $121.3$ | $125.1$ | $128.4$ |