Shedding some light
Make an estimate of how many light fittings you can see. Was your
estimate a good one? How can you decide?
Age
7 to 11
Challenge level
Problem
Image
Look carefully at the image above.
Make an estimate of how many light fittings you can see.
Now count them.
What do you estimate the total number of lights on the fitting to be?
How can you decide if your estimate is a good one?
Did others make better (or worse) estimates? How can you decide?
What else do you notice about the light fittings?
Now, look carefully at the rods that the light fittings are attached to:
- What do you notice?
- How many rods are there?
- How many different shapes can you see?
- Is the resulting figure regular?
Student Solutions
Gurjeet from Cranford Community College says:
There are 6 straight lines and 5 lights on each 6*5= 30 so there are 30
Eleanor sent in her solution to the rest of the problem:
I guessed that there were about 25 lights in the picture. When I counted them there were 28, but I think there are some that you can't see behind the metal bits. My guess was quite a good one because it was only 3 away from the real number that you can see in the picture. It looks like there are 6 rods, and if they all have the same number of lights then the total should be 30, so I think there are two more lights that are hidden. The shape in the middle is a pentagon, but one of the rods doesn't fit in with the rest.
Thank you Eleanor and Gurjeet!