Question

the thickness of Jacob cell phone is 3/8 in the thickness of Crosby cell phone is less than that of Jacob's which measurements could be the thickness of Crosby cell phone?

Answer 1

To compare 3/8 and 4/7 we need to express both fractions with the same denominator:

$\begin{gathered} \frac{3}{8}=\frac{3\cdot7}{8\cdot7}=\frac{21}{56} \\ \frac{4}{7}=\frac{4\cdot8}{7\cdot8}=\frac{32}{56} \end{gathered}$

Then:

$\begin{gathered} \frac{21}{56}<\frac{32}{56} \\ \frac{3}{8}<\frac{4}{7} \end{gathered}$

Therefore, 4/7 inch is not correct

Similarly, we can compare 3/8 and 2/5, as follows:

$\begin{gathered} \frac{3}{8}=\frac{3\cdot5}{8\cdot5}=\frac{15}{40} \\ \frac{2}{5}=\frac{2\cdot8}{5\cdot8}=\frac{16}{40} \\ \frac{15}{40}<\frac{16}{40} \\ \frac{3}{8}<\frac{2}{5} \end{gathered}$

Therefore, 2/5 inch is not correct

Similarly, we can compare 3/8 and 1/3, as follows:

$\begin{gathered} \frac{3}{8}=\frac{3\cdot3}{8\cdot3}=\frac{9}{24} \\ \frac{1}{3}=\frac{1\cdot8}{3\cdot8}=\frac{8}{24} \\ \frac{8}{24}<\frac{9}{24} \\ \frac{1}{3}<\frac{3}{8} \end{gathered}$

Therefore, 1/3 inch is correct

Comparing 3/8 and 5/6, we get:

$\begin{gathered} \frac{3}{8}=\frac{3\cdot6}{8\cdot6}=\frac{18}{48} \\ \frac{5}{6}=\frac{5\cdot8}{6\cdot8}=\frac{40}{48} \\ \frac{18}{48}<\frac{40}{48} \\ \frac{3}{8}<\frac{5}{6} \end{gathered}$

Therefore, 5/6 inch is not correct