Question

a classroom is 12m long, 7m wide and 4m high. find the cost of repairing the walls and ceiling at rate of ₹ 15 per square metre.

Answer 1

ANSWER = ₹ 3540

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EXPLANATION STEP BY STEP

given l=12m, b = 7m , h=4m

surface area of 4 wall and ceiling of room
= lb + 2 (bh + hl)
=12×7 + 2( 7×4+ 4×12)
=84 + 2(28+48)
=84 + 152
= 236 m2

So cost of repairing
= 236×15
=3540 rupees

HOPE IT WILL HELP U

Answer 2

length=12m

breadth=7m

Height=4m

Total surface area = 2(lb+lh+bh)

= 2((12×7)+(12×4)+(7×4))

=2(84+48+28)

=2(160)

=320m^2

Area of floor=l×b

=12×7

=84

Area to be repaired=320-84

=236m^2

Cost to repair 1m^2=RS 15

Cost to repair 236m^2 = 236×15

= RS 3540

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