Elementary Technical Mathematics

$P=14\dfrac{1}{2}$
Substitute the given values of $l$ and $w$ into the formula to obtain: $P=\left(2 \times 4\dfrac{3}{4}\right) + \left(2 \times 2\dfrac{1}{2}\right)$ Write each mixed number as an improper fraction to obtain: $P=\left(2\times \frac{4(4)+3}{4}\right) +\left(2 \times \frac{2(2)+1}{2}\right) \\P=\left(2 \times \frac{19}{4}\right)+\left(2 \times \frac{5}{2}\right)$ Cancel common factors to obtain: $\require{cancel} \\P=\left(\cancel{2} \times \frac{19}{\cancel{4}^2}\right)+\left(\cancel{2} \times \frac{5}{\cancel{2}}\right) \\P=\dfrac{19}{2} + 5 \\P=9\dfrac{1}{2}+5 \\P=(9+5)+\dfrac{1}{2} \\P=14+\dfrac{1}{2} \\P=14\dfrac{1}{2}$