Problem: a hiker walked for 3 days . she walked 18 miles on the first day , walking 3 miles per hour . on the second day she walked for one less hour but she walked one mile per hour , faster than on the first day . on the third day she walked at 7 miles per hour for 2 hours . how many miles in total did she walk ?
Rationale: "first day - 18 miles with 3 miles per hours then total - 6 hours for that day second day - 4 miles per hour and 5 hours - 20 miles third day - 7 miles per hour and 2 hours - 14 miles total 18 + 20 + 14 = 52 answer : option b ."
annotated_formula: add(add(18, multiply(7, const_4)), multiply(7, 2))