Roberta

Roberta bought 9/10 pound of raisins. She put 2/5 pounds in bags for her lunch. How many 2/5-pound bags can Roberta fill? Does she have any left over?

Correct answer:

n =  2
x =  0.1 lb

Step-by-step explanation:

$$\begin{gathered} a=\frac{9}{10}=0.9\text{lb} \\ b=\frac{2}{5}=0.4\text{lb} \\ {n}_1=a/b=\frac{9}{10}/\frac{2}{5}=\frac{9}{10}:\frac{2}{5}=\frac{9}{10}\cdot \frac{5}{2}=\frac{9\cdot 5}{10\cdot 2}=\frac{45}{20}=\frac{9}{4}=2\frac{1}{4}=2.25 \\ n=\lfloor n_1\rfloor =\lfloor 2.25\rfloor =2 \end{gathered}$$

$x=a-n\cdot b=\frac{9}{10}-2\cdot \frac{2}{5}=\frac{1}{10}\text{lb}=0.1\text{lb}$

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