Answer: 2.4 m
Explanation:
Distance of girl from lamp after 6 seconds = 1.2×6 = 7.2 m
120 cm = 1.2 m
Let the length of shadow be x
[tex]\frac{4.8}{7.2+x}=\frac{1.2}{x}[/tex]
[tex]\Rightarrow 4.8x=8.64+1.2x[/tex]
[tex]\Rightarrow 4.8x-1.2x=3.6x=8.64[/tex]
[tex]\Rightarrow x=\frac{8.64}{3.6}=2.4[/tex]
The length of shadow is 2.4 m
Hope it helped