Copyright © University of Cambridge. All rights reserved.

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

The mean of a sequence of $64$ numbers is $64$.

The mean of the first $36$ numbers is $36$.

What is the mean of the last $28$ numbers?

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.*