Sugar 9

Joe has two containers of sugar. One container has 1 2/5 cups, and the other has 4 1/10 cups. If he uses 1 4/5 of sugar, how much does he have left?

Correct answer:

x =  3 ⁷⁄₁₀ = 37/10

Step-by-step explanation:

$$\begin{gathered} a=1\frac{2}{5}=1+\frac{2}{5}=\frac{1\cdot 5+2}{5}=\frac{5+2}{5}=\frac{7}{5}=1\frac{2}{5}=1.4 \\ b=4\frac{1}{10}=4+\frac{1}{10}=\frac{4\cdot 10+1}{10}=\frac{40+1}{10}=\frac{41}{10}=4\frac{1}{10}=4.1 \\ c=1\frac{4}{5}=1+\frac{4}{5}=\frac{1\cdot 5+4}{5}=\frac{5+4}{5}=\frac{9}{5}=1\frac{4}{5}=1.8 \\ x=a+b-c=\frac{7}{5}+\frac{41}{10}-\frac{9}{5}=\frac{14}{10}+\frac{41}{10}-\frac{18}{10}=\frac{14+41-18}{10}=\frac{37}{10}=3\frac{7}{10}=3.7 \end{gathered}$$

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