15. how many tons of asphalt concrete will be required to overlay a 2.5 - mile - long, 24 - ft - wide road…

Explanation:

Step1: Convert units

Convert miles to feet ($1$ mile = $5280$ feet), so $2.5$ miles = $2.5\times5280 = 13200$ feet. Convert inches to feet ($1$ foot = $12$ inches), so $3$ inches=$\frac{3}{12}=0.25$ feet.

Step2: Calculate volume

The volume $V$ of the asphalt concrete layer is given by the formula $V = l\times w\times h$ (length $\times$ width $\times$ height). Here, $l = 13200$ feet, $w = 24$ feet, $h=0.25$ feet. So $V=13200\times24\times0.25$. $$V = 13200\times6=79200\space ft^{3}$$

Step3: Calculate mass from density

Density $\rho = 147.9$ pcf (pounds per cubic foot). Mass $m=\rho\times V$. So $m = 147.9\times79200$. $$m=147.9\times79200 = 11713680\space pounds$$

Step4: Convert pounds to tons

Since $1$ ton = $2000$ pounds. Let the number of tons be $n$. Then $n=\frac{11713680}{2000}$. $$n = 5856.84\space tons$$

Answer:

$5856.84$ tons