Question

A room is 10 m long , 6 m wide and 4.2 m high . It has one door of 2.5 m × 1.5 m and one window of dimension 1.5 m × 1. Find the cost of whitewashing the walls at ₹2.50 per sq. M

Answer 1

area of room=2×h(l+b)
=2×4.2 (10+6)
=8.4×16
=134.4sq.m
area of door =2.5×1.5
=3.75sq.m
area of Window =1.5×1
=1.5sq.m
area of walls=room-door-window
=134.4 -3.75 -1.5
=132.15sq.m
cost of whitewashing =132.15×2.50
=333.075rupees

Answer 2

length=10m

breadth=6m

height =4.2m

dimension of door=2.5×1.5

dimension of window =1.5×1m

area of whitewashing =area of floor-area of door -area of window

= 2(l+b)×h-2.5×1.5-1.5×1

=2(10+6)×4.2-2.5×1.5-1.5×1

134.4-3.75-1.5

129.15

coat of whitewashing =2.50×129.15

322.875