Question

If a bucket of paint of 4.28 litres covers wall area of 48.0 $m^2,$ what is the thickness of layer of paint on the wall?

• A. $8.9\times {10}^{-2}$ mm
• B. $8.90\times {10}^{-2}$ mm
• C. $9\times {10}^{-2}$ mm
• D. None

Answer 1

The correct option is B $8.90\times {10}^{-2}$ mm


Volume = A $\times$ thickness
$V=A\times t$
$t=\frac{V}{A}=\frac{4.28\times {10}^{-3}}{48}$
$=.089\times {10}^{-3}$
The least number of significant figures in the values given are 3.
Therefore, the thickness is written as,
$=8.90\times {10}^{-5}mm$
$=8.90\times {10}^{-2}mm$ (3 significant figures)