WAEC 2020 · Paper 1 · Q40

Consider the statements:

$x$ : Birds fly

$y$ : The sky is blue.

Which of the following statements can be represented as $x \Leftrightarrow y$ ?

Worked solution (try it first)

The symbol $\Leftrightarrow$ is the biconditional: $x$ implies $y$ and $y$ implies $x$ .
In words it is " $x$ if and only if $y$ ".
So $x \Leftrightarrow y$ reads "Birds fly if and only if the sky is blue", option B.