Solution: Let the original speed of the blue car x m/s and the red car x+ 1 m/s.
It is known that the speed of the red car will remain the same for these two minutes.
So the red car walked 120(x+ 1) meters in these two minutes.
The blue car only walked 60x meters in the first minute.
To catch up with the red car in the second minute, it must walk at least 120(x+ 1)-60x meters in the second minute. That is (60x+ 120) meters.
In mathematics
Expressions refer to expressions listed when calculating numbers (or algebraic expressions), including numbers (or letters instead of numbers) and operation symbols (four operations, powers, roots, factorials, permutations and combinations, etc. ). According to the different calculation methods, the formulas are generally divided into horizontal and vertical. Unlike expressions, expressions are the same type of data (such as constants, variables, functions, etc. ).