When asked how old she was, the teacher replied: My age in years is not prime but odd and when reversed and added to my age you have a perfect square...
Can you work out how many of each kind of pencil this student bought?
Add up all 5 equations given below. What do you notice? Solve the system and find the values of a, b, c , d and e. b + c + d + e = 4 a + c + d + e = 5 a + b + d + e = 1 a + b + c + e = 2 a + b + c + d = 0
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.