Question

1. to paint the walls of a rectangular room that is 10 meters long, 8 meters wide, and 2.5 meters high with two coats of paint. if one liter of paint covers 10 sq ft, how many liters are needed?

a 164
b 72
c 18
d 26

Explanation:

Step1: Calculate the area of the walls

The room has two pairs of opposite walls. The area of the walls is \(2\times(10\times2.5 + 8\times2.5)\).
First, calculate \(10\times2.5=25\) and \(8\times2.5 = 20\). Then \(25 + 20=45\), and \(2\times45 = 90\) square - meters. Since there are two coats of paint, the total area to be painted is \(2\times90=180\) square - meters.

Step2: Calculate the amount of paint

If one liter of paint covers \(1.1\) square - meters, then the number of liters of paint \(n=\frac{180}{1.1}\approx163.64\). Rounding up (because we can't buy a fraction of a liter in practice), we need \(164\) liters of paint.

Answer:

A. 164