Ben has

Ben has three rolls of border paper. Each roll has 10 4/5 feet of border. He will need 40 1/3 feet of the border for her room. How much more border does he need?

Correct answer:

x =  7 ¹⁴⁄₁₅ = 119/15 ft

Step-by-step explanation:

$$\begin{gathered} a=10\frac{4}{5}=10+\frac{4}{5}=\frac{10\cdot 5+4}{5}=\frac{50+4}{5}=\frac{54}{5}=10.8\text{ft} \\ b=40\frac{1}{3}=40+\frac{1}{3}=\frac{40\cdot 3+1}{3}=\frac{120+1}{3}=\frac{121}{3}\doteq 40.3333\text{ft} \\ t=3\cdot a=3\cdot \frac{54}{5}=\frac{3\cdot 54}{5}=\frac{162}{5}=32.4\text{ft} \\ x=b-t=\frac{121}{3}-\frac{162}{5}=\frac{605}{15}-\frac{486}{15}=\frac{605-486}{15}=\frac{119}{15}=\frac{119}{15}\text{ft}=7\frac{14}{15}\text{ft}=7.9333\text{ft} \end{gathered}$$

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