Property Income

Janet granted a lease to Jack on 1 March 2014 for a period of 40 years. Jack paid a premium of 25000. But regranted a lease to Jill on 25 March 2014 for a period of 10 years. Jill paid a premium of 15000. Is it right to calculate the Jack's property incom like this? Premium.............................................15000 (-) 15000 x (10-1) x 2%.........................(2700) ` ..........................................................12300 (-) 5500 x 10/40....................................(1375) W Property Income ...................................10925 Working Premium.........................................25000 (-) 25000 x (40-1) x 2%....................(19500) ` ......................................................5500