What is the volume of this cone? i really need , you!

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

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

Ill mark the brainliest if you me with the these three questions 7,8,9