Answer:
A 'kink' in the glass tube which breaks the mercury as it contracts, storing the highest temperature reading. The glass tube is shaped like a lens to magnify the thin mercury thread. Shaking the thermometer resets the mercury back into the bulb.
Number of miles that marker shows when passes through town= 160 miles.
Number of miles that marker shows currently to John = 115 miles.
We need to find the distance between town and John's current location.
For the problem, we can clearly see that Town is at 160 miles away but when John passes the marker shows 115 miles.
So, it's just the difference between 160 miles and 115 miles.
In order to find that difference, we need to subtract those two numbers.
160miles - 115miles = 45 miles.
So, we could say the distance between town and John's current location is 45 miles.