You by 100 sweets for a total cost of $15.00.what did you buy if these are the prices : candy bar-$.50 gum ball-$0.05 cotton candy-$1.00

Ca + g +co = 100 ;
ca*0.50 + g*0.05 + co*1.00 = 15.00 ;  / * 20
where ca = numbers of candy bar; g = numbers of gum ball; co = numbers of cotton candy;

We have to combine ca + g + co = 100 with 10ca + g + 20co =300 ;

10ca - ca + g - g +20co - co = 200;

9ca + 19co = 200;

ca = 18; co = 2 and g = 100 - ( 18 + 2 ) = 80.