Silver line
Weekly Problem 40 - 2008
A class raises money for charity by placing 10p pieces edge to edge in a 'silver line'. If the line was 25m long, how much money did they make?
A class raises money for charity by placing 10p pieces edge to edge in a 'silver line'. If the line was 25m long, how much money did they make?
Age
11 to 14
Challenge level
Problem
A class decides to raise money for charity using a 'silver line'. They invited people to put 10p pieces edge to edge to make a long line. The completed line was 25m long. Roughly how much money did they make?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
Student Solutions
A 10p piece has a diameter of roughly 25mm = 0.025m, so there were approximately 25 $\div$ 0.025 = 1000 coins on the line. This means that the class raised about 1000 $\times$ 10 = 10000p = 100 pounds.