Janna 2

Janna lives 4 3/10 miles from school. She estimates she travels 4 x 2 x 5 or 40 miles weekly. Is her estimate an overestimate or an underestimate? Explain.

Correct answer:

x = underestimate

Step-by-step explanation:

$$\begin{gathered} a=4\frac{3}{10}=4+\frac{3}{10}=\frac{4\cdot 10+3}{10}=\frac{40+3}{10}=\frac{43}{10}=4\frac{3}{10}=4.3\text{mi} \\ b=4\cdot 2\cdot 5=40\text{mi} \\ n=2\cdot 5=10 \\ A=n\cdot a=10\cdot \frac{43}{10}=\frac{10\cdot 43}{10}=\frac{430}{10}=43\text{mi} \\ 43mi>30mi \\ A>b \\ x=underestimate \end{gathered}$$

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