CTET 2 Math and Science 21 Jan 2024 Paper

Thickness of Wood $=3\mathit{c}\mathit{m}$
Length $=1.48\mathit{m}=148\mathit{c}\mathit{m}$
Breadth $=1.16\mathit{m}=116\mathit{c}\mathit{m}$
Height $=83\mathit{c}\mathit{m}$
Inner length $=$ Outer length - twice width $=148-6=142\mathit{c}\mathit{m}$
Breadth $=116-6=110\mathit{c}\mathit{m}$
Height $=80\mathit{c}\mathit{m}$ [ since it is open box]
Area of inner surface $=2\left(\mathit{l}\mathit{b}+\mathit{b}\mathit{h}+\mathit{h}\mathit{l}\right)-\mathit{l}\mathit{b}=2\left[142\times 110+110\times 80+80\times 142\right]-\left[142\times 110\right]=55940\mathit{c}{\mathit{m}}^2=5.5940{\mathit{m}}^2$
The cost of painting its inner surface at ₹150 per m²
So, The Cost of Painting its inner surface $=150\times 5.5940{\mathit{m}}^2=\mathit{₹}839.10$