a man can row 9 kmph in still water . when the river is running at 1.2 kmph , it takes him 1 hour to row to a place and black . how far is the place ?
"m = 9 s = 1.2 ds = 9 + 1.2 = 10.2 us = 9 - 1.2 = 7.8 x / 10.2 + x / 7.8 = 1 x = 4.42 . answer : b"
multiply(divide(multiply(add(9, 1.2), subtract(9, 1.2)), add(add(9, 1.2), subtract(9, 1.2))), const_2)