The cost of packaging of the mangoes is 40% the cost of fresh mangoes themselves. The cost of mangoes increased by 30% but the cost of packaging decreased by 50%, then the percentage change of the cost of packed mangoes, if the cost of packed mangoes is equal to the sum of the cost of fresh mangoes and cost of packaging :

Explanation:-

Cost of fresh mangoes + Cost of packaging = Total cost.

Let initial Cost of fresh, mangoes = 100.
Then, packaging cost = 40.
Thus, Initial total cost = 100 + 40 = 140

After increasing in cost of fresh mangoes 30%,
Cost of fresh mangoes = 130
And cost of packing go down by 50 % so,
Cost of packing = 20.
Now Total cost = 130 + 20 = 150.

Increased cost = 150 - 140 = 10.
% increased = (10*100) /140 = 7.14%.