Mang Ben

Mang Ben took 7 3/10 meters of copper wire for the electrical wiring from a coil of wire 13 7/15 meters long. How much copper wire was left from the coil?

Correct answer:

x =  6 ¹⁄₆ = 37/6 m

Step-by-step explanation:

$$\begin{gathered} a=7\frac{3}{10}=7+\frac{3}{10}=\frac{7\cdot 10+3}{10}=\frac{70+3}{10}=\frac{73}{10}=7.3\text{m} \\ b=13\frac{7}{15}=13+\frac{7}{15}=\frac{13\cdot 15+7}{15}=\frac{195+7}{15}=\frac{202}{15}\doteq 13.4667\text{m} \\ x=b-a=\frac{202}{15}-\frac{73}{10}=\frac{404}{30}-\frac{219}{30}=\frac{404-219}{30}=\frac{185}{30}=\frac{37}{6}\text{m}=6\frac{1}{6}\text{m}=6.1667\text{m} \end{gathered}$$

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