Years Purchase In perpetuity          
no income tax          
(quarterly in advance)          
1        
4[1 - (1+r)-1/4       
Amount (£)      
Interest Rate (%)        
    (n)    
Answer (£)        
(1+r)   Effective yield [r] (1+i/p)^p -1  
(1+r)-1/4   p = no of times int    
1 - (1+r)-1/4   is received and  
4[1 - (1+r)-1/4    compounded     
1     during the year    
4[1 - (1+r)-1/4