Mother 16

Mother cooks food in 1 3/4 hours and prepares the children's snack in 4/6 of an hour. How much longer does she cook the food than prepare the children's snacks?

Correct answer:

x =  1 ¹⁄₁₂ = 13/12 h

Step-by-step explanation:

$$\begin{gathered} a=1\frac{3}{4}=1+\frac{3}{4}=\frac{1\cdot 4+3}{4}=\frac{4+3}{4}=\frac{7}{4}=1.75\text{h} \\ b=4/6=\frac{2}{3}\doteq 0.6667\text{h} \\ x=a-b=\frac{7}{4}-\frac{2}{3}=\frac{21}{12}-\frac{8}{12}=\frac{21-8}{12}=\frac{13}{12}=\frac{13}{12}\text{h}=1\frac{1}{12}\text{h}=1.0833\text{h} \end{gathered}$$

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