Question

A solid box with height 90cm, width 70cm and length 90cm needs to be painted.

The paint costs £0.02 per cm2.
How much will it cost to paint the outside of the box?

Answer 1

£828

Explanation:

The first step to solve this problem is to find the surface area of the solid box. The formula for surface area for a rectangular prism is
`2(wl+hl+hw)`where w is width, l is length, and h is height. Plugging values in gives
`2(90*90+70*90+70*90)=41400` cm^2.

Because each cm^2 of paint costs £0.02, a ratio can be created.

`(1)/(0.02) =(41400)/(x)`

Cross multiplying gives:
`x=828`, so to paint the whole outside of the box, it would cost £828.