As he rides the train to work on a -4˚C winter day, Mr. Teak notices that he can hear the click of the train going over

[answerhappygod]

As he rides the train to work on a -4˚C winter day, Mr. Teak
notices that he can hear the click of the train going over the
spaces between the rails. Six months later, on a 30˚C summer day,
the rails are pushed together and he hears no clicks. If the rails
are 5 meters long when the temperature is 30˚C, how large a gap is
left between the steel rails ( 𝛼𝑠𝑡𝑒𝑒𝑙 = 1.2 × 10−5 °𝐶 −1 ) on the
cold winter day