Question

Length of a rectangular is increased by 20 % and breadth is decreased by 10% then perimeter is

Answer 1

Let the Initial Length of rectangle be L and Breadth be B
Let the new Length of rectangle be L' and Breadth be B'

Let Initial Perimeter be P and New Perimeter be P'

According to the question,  New length is 20% more than the initial length
Thus, 
                              L' = L + 20% of L
                              L' = L + 0.20 L
                              L' = 1.2 L
   and also new breadth is 10% less than the initial breadth,

So,                         B' = B - 10% of B
                              B' = B - 0.1 B
                              B' = 0.9 B
Now the perimeter can be calculated as, 

                             P' = 2 (L' + B')
                             P' = 2 (1.2 L + 0.9 B)
                             P' = 2.4 L + 1.8 B
This way we can calculate the new perimeter