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bridges on highways have expansion joints, which are small gaps in the roadway between one bridge section and the next. the gaps are put there so the bridge will have room to expand when the weather gets hot. suppose a bridge has gap of 1.4 cm when the temperature is 30c, and that the gap narrows to 0.9 cm when the temperature warms to 40c.
find the rate of expansion from 20c to 30c do not round