Some might call it karma...

London Mayor Boris Johnson had to admit, "No one said IQ is the only measure of ability," after failing to answer questions presented in the form of an IQ test while on an LBC radio phone-in.

When he was asked how many apples he would have if he took two apples from three, Johnson said, "You've got loads of apples mate, you've got one apple left."

Presenter Nick Ferrari replied, "You say you've got one apples? You haven't, you've got two apples."

Oops.

To be fair, the next one might be hard for a digital generation: "I went to bed at 8 in the evening last night and I wound up my clock and set my alarm to sound for 9 o'clock in the morning. How many hours sleep did I get?"

You might say 13, but actually wind-up clocks don't distinguish between a.m. and p.m., so the correct answer is one hour.

Johnson, meanwhile, refused to answer, protesting, "This is not about me."

What prompted the grilling?

Johnson stirred controversy last week when he seemingly blamed people's intelligence or lack thereof for economic inequality. He said:

"Whatever you may think of the value of IQ tests, it is surely relevant to a conversation about equality that as many as 16 per cent of our species have an IQ below 85, while about 2 per cent have an IQ above 130. The harder you shake the pack, the easier it will be for some cornflakes to get to the top."

On the radio show Tuesday, Johnson defended his remarks, saying he meant there was "too much inequality." He said his remarks had been "willfully" misinterpreted and misconstrued by other politicians.

The Daily Telegraph has all three questions Johnson was asked if you want to test your knowledge.