calculate how much time could be saved if the train would run at its usual speed , given that it ran at 5 / 7 of its own speed and got to its destination in 15 hours ?
"new speed = 5 / 7 of usual speed new time = 5 / 7 of usual time 5 / 7 of usual time = 15 hrs usual time = 15 * 5 / 7 = 10.71 hrs time saved = 15 - 10.71 = 4.29 hrs answer is c"
add(divide(reminder(subtract(multiply(15, const_60), multiply(multiply(15, divide(5, 7)), const_60)), const_60), const_100), floor(divide(subtract(multiply(15, const_60), multiply(multiply(15, divide(5, 7)), const_60)), const_60)))