Problem: yesterday it took robert 4 hours to drive from city a to city b . today it took robert 2.5 hours to drive back from city в to city a along the same route . if he had saved 15 minutes in both trips , the speed for the round trip would be 70 miles per hour . what is the distance between city a and city b ?
Rationale: "2 d / 70 = 6 ( because time = 4 + 2.5 - 0.5 hrs ) = > d = 210 answer - d"
annotated_formula: divide(multiply(70, subtract(add(4, 2.5), const_1)), const_2)