# Percentage Problem 13

### From Homeworkwiki

**The cost of manufacturing an article is divided between material and labor in the ratio of 8 : 7.**

**If the cost of material is increased by 40 % and the cost of labor is reduced by 20 %, find the resulting**

**change, as per cent in the total cost.**

**Solution:** Given the ratio between the cost of material and the cost of labor is 8 : 7

=> If the cost of material is $ 8, the cost of labor is $ 7

And, so the total original cost of the article is $ 8 + $ 7 = $ 15

Now, the new cost of material = $ 8 + 40 % of $ 8 = $ 11.20

and the new cost of labor = $ 7 - 20 % of $ 7 = $ 5.60

Therefore, Total new cost of the article = $ 11.20 + $ 5.60 = $ 16.80

=> Increase in cost = $ 16.80 - $ 15 = $ 1.80

And, resulting change (increase) = 1.80 / 15 X 100 % = 12 %