This problem solving activity has a measurement focus.
Adam bought a watch for 50c.
Unfortunately it gains 30 minutes every day!
If Adam set his watch at noon one day, how long would it be before it next correctly shows 12 o’clock again?
The problem uses analogue time and logic. To solve this problem, students will need to know and be able to work with standard units of time including minutes, hours, days and days in one year. Possible methods of solution might include using a series of diagrams, being systematic or carefully using arithmetic.
Adam bought a watch for 50c. Unfortunately it gains 30 minutes every day! If Adam set his watch at noon one day, how long would it be before it next correctly shows 12 o’clock again?
Adam has another watch that loses a minute a day. How long will it take to show 12 o'clock at midday?
After the first 24 hours Adam’s watch will show 12:30 at midday. After the second day it will show 1:00 at that time. After 24 days Adam’s watch will show 12:00 at 12 o’clock.
After 60 days it will show 11 o'clock at midday. Therefore it will take 12 x 60 = 720 days to show the correct time. 720 days = 1 year and 355 days (using 365 days in a year).
Printed from https://meaningfulmaths.nt.edu.au/mmws/nz/resource/adam-s-watch at 8:56pm on the 26th February 2024