Copyright © University of Cambridge. All rights reserved.

## 'Baby's Weight' printed from http://nrich.maths.org/

Weighing the baby at the clinic was a problem. The baby would not keep still and caused the scales the wobble. So I held the baby and stood on the scales while the nurse read off $78 \; \text{kg}$. Then the nurse helf the baby while I read off $69 \; \text{kg}$. Finally I held the nurse while the baby read off $137 \; \text{kg}$. What is the combined weight of all three (in $\text{kg}$)?

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.*

*View the archive of all weekly problems grouped by curriculum topic*