Given f(x) = the quantity of 4x plus 1, divided by 3, solve for f−1(3)

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)

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

Fifty students are trying to raise at least 12,500 for a class trip. they have already raised 1,250. how much should each student raise on average in order to meet the goal? write and solve the two step inequality for this problem