A towel, when bleached, was found to have lost 20% of its length and 10% of its breadth. The percentage of decrease in area is:
বিকল্পসমূহ (নিজের উত্তর যাচাই করতে ক্লিক করুন):
সঠিক উত্তর
3 (28%)
বিস্তারিত ব্যাখ্যা ও বিশ্লেষণ:
Solution:
Let the length of the rectangle be 10x cm and the breadth be 10y cm.
The original area of the rectangle is given by:
Original Area = 10x × 10y = 100xy
After the reduction, the length becomes:
New Length = 10x × (80/100) = 8x
And the breadth becomes:
New Breadth = 10y × (90/100) = 9y
The new area after reduction is:
New Area = 8x × 9y = 72xy
The change in area is:
Change in Area = 100xy - 72xy = 28xy
The percentage decrease in area is:
Percentage Decrease = (28xy / 100xy) × 100 = 28%
Conclusion:
The decrease in the area is 28%.
