Question

18. The dimensions of a room is 7mx7mx10m. Find the cost of white the four wall at a rate
of Rs 5 per m2
19. A cube is made of Mattel having edge 10cm. Find the cost of making at a rate of 15 per m²​

Answer 1

18

Answer:

to find the cost of white the four wall first we have to find the surface area of four wall

room is in the shape of cuboid find the lateral surafce area of cuboid

s. a of four wall =lateral surafec area of cuboid

=2h(l+b)

=2*10(7+7)

=20*14

= 280 m^2

cost of white wash for 1m^2 wall is=5rs

cost of white wash for 280m^2 is=5*280=1400rs

so ans is 1400 rs (ans)....

q19

tsa of cube=6a^2

tsa of cube =6*(10*10) cm^2

=600cm^2

= 600*10^-4m^2

1m^2 cost=15 rs

600*10^-4 cost=15*600*10^-4 rs

=.9 rs.... (ans)..