Question

Which is greater, 1/2 or 2/7?

Answer 1

If we have two fractions a/b and c/d:

`(a)/(b)(\text{ })(c)/(d)`

To determine which one of them is greater we make the cross product:

`ad(\text{ })bc`

We have 3 cases:

- If ad is greater than bc, then a/b is greater than c/d

- If bc is greater than ad, then c/d is greater than a/b

- If ad is equal to bc, then a/b is equal to c/d

For 1/2 and 2/7:

`\begin{gathered} (1)/(2)(\text{ })(2)/(7) \\ 7\cdot1(_(\square))2\cdot2 \\ 7>4 \\ \Rightarrow(1)/(2)>(2)/(7) \end{gathered}`