There's a possible explanation that is totally in support of the Africans, EVEN if the claim was true. Here it is:

IQ tests are culturally biased.

Where did this explanation come from? The way you present it, it's as if you looked for this explanation in order to save a belief about the intelligence of Africans.

If the test asks "How do you use a teacup?"

I have seen a few IQ tests, and none of them contain questions remotely like this. This imaginary IQ test question seems to have been invented as fictional evidence to support the explanation.

IQ tests these days are typically "culture-fair", by which is meant that the questions are non-verbal and non-pictorial. At least, that is what is usually meant, although on googling for "culture-fair", I did notice the occasional assumption that a test that gives different average scores to people from different cultures is ispo facto not culture-fair, making equality of IQ between cultures an axiom instead of an observation.