AB and Co. holds a lease of minerals from RS Ltd for a period of 40 years from 1 October 1997.Under this lease, there is payable a royalty of Sh.100 per tonne merging in a minimum rent of Sh20,000 per year payable yearly on 30thSeptember and 31stMarch.They granted a sub-lease for 20 years from 1 April 1998 to XY Co. Ltd for a royalty of Sh150 per tonne merging in a minimum rent of sh15,000 per half year, payable yearly on 31stMarch and 30thSeptember.

AB and Co are entitled to recoup shortworkings from RS Ltd throughout the lease term, but the sub-lease allows XY Co. Ltd to recoup shortworkings only out of excess workings in any of the three half-years immediately following that in which shortworkings accrued:

The mining work was as follows:

By AB & Co.By XY & Co.

Half year ended:(Tonnes)(Tonnes)

31 March 199850-

30 September 19985050

31 March 199920060

30 September 199930060

31 March 2000250120

Requred:Show the necessary accounts in the books of AB & Co. Ltd.The books are balanced each year on 31stMarch.