From a 12 foot roll of rubber hose, a person cuts lengths of 2 3/8 feet, 2 1/2 feet, and 3 1/4 feet. How much hose is left on the roll?

Respuesta :

Sum the lengths that the person cuts:

To sum mixed numbers:

[tex]2\frac{3}{8}ft+2\frac{1}{2}ft+3\frac{1}{4}ft=[/tex]

1. Add the whole numbers:

[tex]2ft+2ft+3ft=7ft[/tex]

2. Add fractions

[tex]\begin{gathered} \frac{3}{8}ft+\frac{1}{2}ft+\frac{1}{4}ft \\ \\ \text{Write all as fractions with denominator 8:} \\ \\ \frac{3}{8}ft+\frac{4}{8}ft+\frac{2}{8}ft=\frac{3ft+4ft+2ft}{8}=\frac{9}{8}ft \\ \\ \\ \end{gathered}[/tex]

Then, the person cuts 7 9/8 ft, substract it from the initial 12 ft roll of rubber hose:

[tex]\begin{gathered} \text{Write the mixed number as a fraction:} \\ 7\frac{9}{8}ft=7ft+\frac{9}{8}ft=\frac{56ft+9ft}{8}=\frac{65}{8}ft \\ \\ \text{Substract the fraction above from 12ft}\colon \\ \\ 12ft-\frac{65}{8}ft=\frac{96ft-65ft}{8}=\frac{31}{8}ft \\ \\ \text{Write the result as a mixed number:} \\ \\ \frac{31}{8}ft=\frac{24}{8}ft+\frac{7}{8}ft=3\frac{7}{8}ft \end{gathered}[/tex]

Then, 3 7/8 ft of hose are left on the roll