In her acceptance speech, Nishi, from Manchester, told viewers she hoped her performance would inspire other girls to pursue traditionally male-dominated subjects such as maths.
She said: 'One of the main reasons I entered myself in the competition was to show there are a lot of stereotypes about girls not being able to do maths or physics, for example. I'd like to show that that's not true at all.' Nishi's Sri Lankan parents Neelanga Uggalle, who is vice-president for IT security at Barclays, and Shiromi Jayasinghe, her accountant mother, looked on proudly from the audience as she spoke.
While many of the show's 19 entrants appeared to have pushy parents behind them, Nishi put herself forward for the prize.
Mr Uggalle, who has nicknamed her the 'human calculator', said: 'I don't think we call ourselves pushy parents simply because I think Nishi is the pushy one.'
The 'proud geek' has an IQ of 162. Einstein and Hawking are believed to have scored 160.
CAN YOU ANSWER HER WINNING QUESTIONS?
1: In 2011 the first synthetic trachea transplant was achieved by using the patient's own what?
2: What is 411?+?854?+?156?+?625?
3: Upright plants such as cooksonia first emerged in which geological period?
4: What is 24?x?9?–?16?x?9/8?
5: What name is given to the period of extremely rapid expansion of the universe immediately after the Big Bang?
6: What is the name of a long cigar-shaped mound of till that has been smoothed in the direction of a glacier's flow?
7: Beginning with C, what process do alkanes undergo to make alkenes?
ANSWERS
1: Stem cells 2: 2,046 3: Silurian 4: 225 5: Cosmic inflation 6: Drumlin 7: Cracking