Answer: For 40, The speed of the boat is 14 mph and the current is 10 mph downstream. For 41, the vans can carry 10 students and the buses can carry 52 students.
Explanation:
40. Find the mph speed by dividing the miles by the hours for upstream and downstream, get the mean of those 2, and thats the speed in still water. For the speed of the current, subtract the downstream speed by the still water speed, and thats the current speed. Since the number is positive, you know that the current goes downstream, otherwise it would hinder the still speed and the number would be negative.
41. 9x+14y=818 and x+7y=374, multiply x+7y=374 by 2 on each side, subtract, and simplify.