Question

For exercises 71-73, use the following information.

The First Transcontinental Railroad was built by two companies. The Central Pacific began building eastward from Sacramento, California, while the Union Pacific built westwards from Omaha, Nebraska. The two lines met at Promontory, Utah, in 1869, about 6 years after construction began.

72. About how many miles of track did each company lay.

Short answer

The miles of track laid by Central Pacific Company and Union Pacific Company are $\mathbf{691}\mathbf{.}\mathbf{2}$ miles and $\mathbf{1083}\mathbf{.}\mathbf{8}$ miles.

Step-by-step solution

­- Description of step.

It is given that the construction was completed in 6 years.

It is known that 1 year=12 months.

Therefore, it can be obtained that:

$\begin{array}{c}\text{6years=6×12months}\\ \text{=72months}\end{array}$

­- Description of step.

It is given that the Central Pacific Company laid an average of $9.6$miles of track per month.

That implies in 1 month it laid $9.6$miles of track.

Therefore, in 72 months it will lay:

$9.6\times 72=691.2$

Therefore, in 72 months it will lay $691.2$miles of track.

It is given that the total of 1775 miles of track has been laid.

Therefore, the sum of the miles of track laid by Central Pacific Company and Union Pacific Company is 1775.

Therefore, it can be obtained that:

$\begin{array}{c}\text{691.2+milesoftracklaidbyUnionPacificcompany=1775}\\ \text{milesoftracklaidbyUnionPacificcompany}+691.2-691.2=1755-691.2\\ \text{milesoftracklaidbyUnionPacificcompany}=1083.8\end{array}$

Therefore, the miles of track laid by Union Pacific Company is $1083.8$miles

­- Description of step.

Therefore, the miles of track laid by Central Pacific Company and Union Pacific Company are $691.2$ miles and $1083.8$ miles.