Answer: 28 color sets were sold
Explanation:
Let x represent the number of black-and - white models that were sold.
Let y represent the number of color sets that were sold.
An appliance dealer sold 40 tv sets during a special sale. Some of the sets were black-and - white models while the rest were color sets.. It means that
x + y = 40
Black-and - white models each sold for $119. Color sets sold at $319each. The sale brought in $10,360. It means that
119x + 319y = 10360 - - - - - -- - - - - -1
Substituting x = 40 - y into equation 1, it becomes
119(40 - y) + 319y = 10360
4760 - 119y + 319y = 10360
- 119y + 319y = 10360 - 4760
200y = 5600
y = 5600/200
y = 28