Question

A huge metallic oil tank depot has radius 3.5m and height 7m .if the whole tank has to be painted how much it will cost at a rate of rupees 350per square meter

Answer 1

Hello Mate!

If we have to paint only curved surface area then,

Surface area of cylinder = 2πrh

= 2 × 22/7 × 3.5 m × 7 m

= 154 m²

Cost of painting = 154 × Rs 350

= Rs 53,900

If we have to paint curved surface area as well as base then,

= 2πrh + πr²

= πr( 2h + r )

= 22/7 × 3.5 m ( 2 × 7 m + 3.5 m )

= 11 m × 17.5 m

= 192.5 m²

Cost of painting = 192.5 × Rs 350

= Rs 67,375

Have great future ahead!

Answer 2

Hay

Dear user -

According to the question we know that A huge metallic oil tank depot has radius 3.5 m
and hight 7m

we need to paint curved surfaces area so, the formula of surface area of cylinder is 2πrh

We know that the value of pi is 22/7,and radius is 3.5m or hight = 7m

Now, put it value in given formula

$2 \times \frac{22}{7} \times 3.5 \times 7$

=> 154m²

Now, cost at a rate of rupees 350 per square meters

so, 154 × 350 = 53900


Now, we painted curved surfaces area and base, then we need the formula (2πrh+πr²)

we get common 2π,the the formula is πr(2h+r)

let's solving,

$\frac{22}{7} \times 3.7(2 \times 7 + 3.5)$

=> 11 + 17.5

=> 192.5m²

now, the cost of painting is 192.5 × 350 = 67375


Hope it helps you