A person standing on the bank of a river observes that the angle of elevation of the top of a tree on the opposite bank of the river is … and when he retires … meters away from the tree the angle of elevation becomes …. The breadth of the river is :

Height and Distance

JEE Main 2004 · Annual, Paper 1 · Q3899

MathematicsMedium38×since 2004Q3899

A person standing on the bank of a river observes that the angle of elevation of the top of a tree on the opposite bank of the river is

{60^ \circ }

and when he retires

40

meters away from the tree the angle of elevation becomes

{30^ \circ }

. The breadth of the river is :