The cost of packaging of the mangoes is 40% the cost of fresh mangoes themselves.

Ques - 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 :

A. 14.17%

B. 7.14%

C. 8.87%

D. 6.66%

Soution - Total cost = Cost of fresh mangoes + Cost of packaging
Let,

The Cost of fresh mangoes = 100

The cost of packaging = 40% of cost of fresh mangoes

The cost of packaging = (40/100) × 100

= 40

Therefore,

Total cost = Cost of fresh mangoes + Cost of packaging

Total cost = 100 + 40

Total cost = 140

After, increasing the cost of fresh mangoes by 30%

New Cost of fresh mangoes = 100 + (30/100) × 100

New Cost of fresh mangoes = 100 + 30

New Cost of fresh mangoes = 130

After, decreasing the cost of packaging by 50 %

New Cost of packaging = 50% of 40

New Cost of packaging = 20

Now,

New Total cost = 130 + 20

New Total cost = 150

Change in cost = 150 - 140 = 10

Percentage change in cost  = (change in cost / initial total cost) × 100

= (10/140) × 100

= 7.14%

Hence,

The correct option is (b) 7.14%