A cylindrical water tank of radius $7$ m and height $10$ m is to be coated on its outer curved surface at…

A cylindrical water tank of radius $7$ m and height $10$ m is to be coated on its outer curved surface at $\text{Rs.}\,30$ per m$^{2}$. The cost is (use $\pi=\dfrac{22}{7}$):
  1. $\text{Rs.}\,13200$
  2. $\text{Rs.}\,6600$
  3. $\text{Rs.}\,9240$
  4. $\text{Rs.}\,26400$

Solution

CSA $= 2\pi r h = 2 \times \dfrac{22}{7} \times 7 \times 10 = 440 \text{ m}^{2}$. Cost $= 440 \times 30 = \text{Rs.}\,13200$.

Asked in: IMO

Practice more MENSURATION questions on Aicharya