The length of a rectangular field is increased by 60 % . By what percent would the width have to be decreased to maintain the same area?

Let length = L and breadth = B
Let , New breadth = Z
Then, New length = ( 160 / 100) L.
= 8L / 5
∴ 8L / 5 x Z = LB
or Z = 5B/8
Decrease in breadth = (B-5B/8)
= 3B/8
∴ Decrease in percent = (3B/8 x1/B ) x 100 %
= 37¹/₂%