Question

the length breadth and height of a room are 5m 4m and 3M respectively find the cost of whitewashing the near of the broom and ceiling at the rate of 50 rupees per square metre

Answer 1

total surface area =2(lb+bh+hl)
=2×47
=94 m sq
area of floor=5×4
=20 m sq
area to be white washed =94 -20
=74
cost=50×74
=3700rs

Answer 2

l = 5m
b = 4m
c = 3m

Area of 4 walls = 2h(l+b)
= 2*3(4m+5m)
= 6(9)sqm = 54sqm

Area of ceiling = lb( because it is a rectangle)
= 5m*4m = 20sqm

so, total area = area of 4 walls + area of ceiling
= 54sqm+20sqm
= 74sqm

cost of whitewashing 1sqm = 50rs
cost of whitewashing 74sqm = 50*74 =3700rs