1 Different types of watches lose accuracy at different rates, as shown in the table below.
Type of watch Seconds gained/lost per 24 hours
Worst Typical Best
Vintage mechanical ±60 ±15 ±5
Modern mechanical ±10 ±5 ±2
Modern quartz ±2 ±1 ±0.1
Marcello has one watch of each type. He synchronises them so that they all show exactly the
same time.
What is the biggest difference there could be between the times shown on two of the watches
after 24 hours?
A 10 seconds
B 20 seconds
C 50 seconds
D 70 seconds