If the concentration x(t) of a certain reactant in a chemical reaction changes according to the relation x'(t) = 0.3x(4-x), find the concentration at which the reaction rate is a maximum.

Aswimming pool is a rectangle with semicircles on the end. the rectangle is 12 meters wide and 30 meters long. the diameter and width of the swimming pool are equal. sketch and label an overhead diagram of the swimming pool. find the area of the swimming pool floor.

Tom wants to order tickets online so that he and three of his friends can go to a water park the cost of the tickets is 16.00 per person there is also a 2.50 one-time service fee for ordering tickets online write an expression in term of n that represents the cost for n ordering tickets online

Determine the number of girls in a math class with 87 boys if there are 25 girls for every 75 boys