algebra
posted by monkeybaby on .
b) Suppose you want to cover the backyard with decorative rock and plant some trees as the first phase of the project. You need 25 tons of rock to cover the area. If each ton cost $70 and each tree is $90, what is the maximum number of trees you can buy with a budget for rock and trees of $3,000? Write an inequality that illustrates the problem and solve. Express your answer as an inequality and explain how you arrived at your answer.

(25 * $70) + $90x < $3000
Can you explain how I got that inequality?
I hope this helps.