A cuboidal slab of copper having dimensions 22 cm × 10 cm × 5 cm is melted and recasted in the form of a wire of 1 mm diameter. The wire is rubber coated at the rate of Rs. 1.50 per meter. Find the cost of rubber coating (in ₹) (Use $\pi =\frac{22}{7}$).
Answer & explanation
Correct answer: option 3
Volume of cuboidal slab = 22 cm × 10 cm × 5 cm = 1100 cubic cm
Volume of wire of 1 mm dia = Πd2h/4 = Π(0.1)2h /4
Given, Volume of cuboidal slab = Volume of wire of 1 mm dia
1100 = Π(0.1)2h/4
h = 4400/Π(0.1)2
h = 140000 cm
The wire is rubber coated at the rate of Rs. 1.50 per meter
Cost of rubber coating of the wire = 1.5*140000/100 = 2100
The correct answer is Option (3) → 2100