Math HW, please help: At its maximum speed, a motorboat can travel 10 miles downstream on a river in 20 minutes. It takes 30 minutes for the boat to travel back upstream the same 10 miles, also at maximum speed.
Write a system of two equations that could be used to find the maximum speed of the motorboat in still water. Let b represent the maximum speed of the motorboat in miles per hour and let r represent the speed of the river's current in miles per hour. Convert the times into hours. Solve the system of equations for b and r to determine the boat's maximum speed in still water and the speed of the river's current.

Can someone 50 first drop menu 0.80 or 0.75 or 1.20 or 4.00 second drop menu 4.00 or 0.75 or 0.25 or 3.75 3rd 15,6,10, or 9 4th yes or no

Antonio made a scale model of a building. the model's scale is 1 inch to 235 feet and its height is 3.5 inches. what is the exact height of the actual building? enter your answer in the box.

Someone answer this asap rn for ! a discount store’s prices are 25% lower than department store prices. the function c(x) = 0.75x can be used to determine the cost c, in dollars, of an item, where x is the department store price, in dollars. if the item has not sold in one month, the discount store takes an additional 20% off the discounted price and an additional $5 off the total purchase. the function d(y) = 0.80y - 5 can be used to find d, the cost, in dollars, of an item that has not been sold for a month, where y is the discount store price, in dollars. create a function d(c(x)) that represents the final price of an item when a costumer buys an item that has been in the discount store for a month. d(c(x)) =