Question

A pole 14 m high casts a shadow of 10 m. At the same time, what will be the height of a tree, the length of whose shadow is 7 metres ?

(a) 20 m (b) 9.8 m

(c) 5 m (d) none of these

Answer 1

Answer : (b)

Let x be the height of tree then the ration's of
Height of pole and tree 14 m : x m
Length of shadow 10 m : 7 m
Less shadow, less height

$\therefore$ By direct proportion

14 : x : : 10 : 7
$\Rightarrow \frac{14}{x}=\frac{10}{7}$

$\therefore x=\frac{14\times 7}{10}=\frac{98}{10}=9.8m$

Height of the = 9.8 m