[We answered this rhetorical question a few years ago, but the vintage illustration is "new," courtesy of
Punch, 1877.]
Q: How many beans make five?
A: It’s something of a trick question. The answer is "one." One leguminous pod contains five seeds.
Note that this riddle is a corruption of "How many beans make
fava." Again, the answer is "one," though admittedly it's one very broad bean.