Family earnings :
?	                          12.50 :                   tax on wages
	                           2.00 :                 family persons

	                       20000.00 :          John's gross earnings
%	                   tax on wages :                          12.50
=	                           0.00 :            John's tax on wages

	          John's gross earnings :                       20000.00
-	            John's tax on wages :                           0.00
=	                       20000.00 :            John's net earnings

	                       15000.00 :          Jane's gross earnings
%	                   tax on wages :                          12.50
=	                        1875.00 :            Jane's tax on wages

	          Jane's gross earnings :                       15000.00
-	            Jane's tax on wages :                        1875.00
=	                       13125.00 :            Jane's net earnings

	            John's net earnings :                       20000.00
	            Jane's net earnings :                       13125.00
=	                       33125.00 :                family earnings

Family expenses :
	              John's cigarettes :                        5020.00
	                     John's gas :                        7160.60
	                    John's rent :                       10050.00
	            John's food for dog :                         525.30
=	                       22755.90 :                John's expenses

	                 Jane's new car :                      150000.00
	                     Jane's gas :                        3500.55
	                    Jane's rent :                        7325.70
=	                      160826.25 :                Jane's expenses

	                John's expenses :                       22755.90
	                Jane's expenses :                      160826.25
=	                      183582.15 :                family expenses

Family balance :
	                family earnings :                       33125.00
-	                family expenses :                      183582.15
?	                     -150457.15 :                 family balance
/	                 family persons :                           2.00
=	                      -75228.57 :      family balance per person