These strange clocks only have an hour hand. Olivia tells you that one of them shows 7:30. Which one is it?
When we think about 7:30, what do we know? 7:30 is halfway between seven o’clock and eight o’clock. Which one of these clocks puts the hour hand halfway between seven and eight? The clock on our left puts the hour hand between six and seven. And the clock on our right puts the hour hand between seven and eight. So we know that only the clock on the right could represent 7:30.