    191

'						
					B'^Ss,"s^	
 =12%						
					\	
 =11% 						< ;4
7 = 8%	~'				^	
/i		L	~~^^^	^^^^		
 = 7% 					^\	s /3
					^s. l-^	
					N	' /2
					i	/1
	10=0	% 	14 =	% 177 = 	% 20% =<  s	0

. 7.7.     

 7-=12% 7-^=11%F = 8%		. '
		񗗗- '4
		3 '2
 7-^=7%		D ^
		 /^
	10% =^	14% 17% 20% ^ '" ^s 

. 7.8.    ,   