What is the shape and height of this distribution?

The production line where you work can assemble 5 appliers every 30 minutes at this rate how long should it take the line to assemble 125 amplifiers

Amountain climber starts a climb at an elevation of 453 feet above sea level at his first rest stop he has climbed 162 feet and by his second rest stop he has climbed another 207 feet its getting late in the day so the climber starts his way down if the climber desends 285 feet how much does he need to ascend or descend to return to the original starting point

Using only the digits 5, 6, 7, 8, how many different three digit numbers can be formed if no digit is repeated in a number?