calculate how much time could be saved if the train would run at its usual speed , given that it ran at 4 / 9 of its own speed and got to its destination in 13 hours ?
"new speed = 4 / 9 of usual speed new time = 4 / 9 of usual time 4 / 9 of usual time = 13 hrs usual time = 13 * 4 / 9 = 5.78 hrs time saved = 13 - 5.78 = 7.22 hrs answer is e"
add(divide(reminder(subtract(multiply(13, const_60), multiply(multiply(13, divide(4, 9)), const_60)), const_60), const_100), floor(divide(subtract(multiply(13, const_60), multiply(multiply(13, divide(4, 9)), const_60)), const_60)))