Copyright © University of Cambridge. All rights reserved.

'Two Girls' printed from http://nrich.maths.org/

Show menu

See all short problems arranged by curriculum topic in the short problems collection


There are $10$ girls in a mixed class.

If two pupils from the class are selected at random, then the probability that both are girls is $0.15$

How many boys are in the class?




If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.






This problem is taken from the UKMT Mathematical Challenges.