A landscaper 3

A landscaper needs 3 4/8 pounds of plant food. He has 1 1/4 pounds in his truck and another 4/6 pound at his shop.

How many more pounds of plant food does the landscaper need?

Correct answer:

m =  1 ⁷⁄₁₂ = 19/12 lb

Step-by-step explanation:

$$\begin{gathered} a=3\frac{4}{8}=3+\frac{4}{8}=\frac{3\cdot 8+4}{8}=\frac{24+4}{8}=\frac{28}{8}=\frac{7}{2}=3.5\text{lb} \\ b=1\frac{1}{4}=1+\frac{1}{4}=\frac{1\cdot 4+1}{4}=\frac{4+1}{4}=\frac{5}{4}=1.25\text{lb} \\ c=\frac{4}{6}=\frac{2}{3}\doteq 0.6667\text{lb} \\ m=a-b-c=\frac{7}{2}-\frac{5}{4}-\frac{2}{3}=\frac{42}{12}-\frac{15}{12}-\frac{8}{12}=\frac{42-15-8}{12}=\frac{19}{12}=\frac{19}{12}\text{lb}=1\frac{7}{12}\text{lb}=1.5833\text{lb} \end{gathered}$$

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