Problem: a student traveled 10 percent of the distance of the trip alone , continued another 30 miles with a friend , and then finished the last half of the trip alone . how many miles long was the trip ?
Rationale: let x be the total length of the trip . 0.1 x + 30 miles + 0.5 x = x 30 miles = 0.4 x x = 75 miles the answer is a .
annotated_formula: divide(30, subtract(subtract(const_1, inverse(10)), divide(const_1, const_2)))